There is a quite huge "uncorrectable error in header" flood in KMSG
on a clean system boot since there is no pstore buffer saved in RAM.
Let's silence the redundant noisy messages by rate-limiting the printk
message. Now there are maximum 10 messages printed repeatedly instead
of 35+.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210302095850.30894-1-digetx@gmail.com

syzbot is hitting WARN_ON(pstore_sb != sb) at pstore_kill_sb() [1], for the
assumption that pstore_sb != NULL is wrong because pstore_fill_super() will
not assign pstore_sb = sb when new_inode() for d_make_root() returned NULL
(due to memory allocation fault injection).

Since mount_single() calls pstore_kill_sb() when pstore_fill_super()
failed, pstore_kill_sb() needs to be aware of such failure path.

[1] https://syzkaller.appspot.com/bug?id=6abacb8da5137cb47a416f2bef95719ed60508a0Reported-by: syzbot <syzbot+d0cf0ad6513e9a1da5df@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210214031307.57903-1-penguin-kernel@I-love.SAKURA.ne.jp

Both pstore_compress() and decompress_record() use a mistyped config
option name ("PSTORE_COMPRESSION" instead of "PSTORE_COMPRESS"). As
a result compression and decompression of pstore records was always
disabled.

Use the correct config option name.
Signed-off-by: Jiri Bohac <jbohac@suse.cz>
Fixes: fd49e032 ("pstore: Fix linking when crypto API disabled")
Acked-by: Matteo Croce <mcroce@microsoft.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210218111547.johvp5klpv3xrpnn@dwarf.suse.cz

Pull LED fix from Pavel Machek:
 "One-liner fixing a build problem"

* 'for-rc8-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/pavel/linux-leds:
  leds: rt8515: add V4L2_FLASH_LED_CLASS dependency

Merge tag 'kbuild-fixes-v5.11-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - Fix CONFIG_TRIM_UNUSED_KSYMS build for ppc64

 - Use pkg-config for scripts/sign-file.c CFLAGS

* tag 'kbuild-fixes-v5.11-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  scripts: set proper OpenSSL include dir also for sign-file
  sparc: remove wrong comment from arch/sparc/include/asm/Kbuild
  kbuild: fix CONFIG_TRIM_UNUSED_KSYMS build for ppc64

Pull x86 fixes from Borislav Petkov:
 "I kinda knew while typing 'I hope this is the last batch of x86/urgent
  updates' last week, Murphy was reading too and uttered 'Hold my
  beer!'.

  So here's more fixes... Thanks Murphy.

  Anyway, three more x86/urgent fixes for 5.11 final. We should be
  finally ready (famous last words). :-)

   - An SGX use after free fix

   - A fix for the fix to disable CET instrumentation generation for
     kernel code. We forgot 32-bit, which we seem to do very often
     nowadays

   - A Xen PV fix to irqdomain init ordering"

* tag 'x86_urgent_for_v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/pci: Create PCI/MSI irqdomain after x86_init.pci.arch_init()
  x86/build: Disable CET instrumentation in the kernel for 32-bit too
  x86/sgx: Maintain encl->refcount for each encl->mm_list entry

The leds-rt8515 driver can optionall use the v4l2 flash led class,
but it causes a link error when that class is in a loadable module
and the rt8515 driver itself is built-in:

ld.lld: error: undefined symbol: v4l2_flash_init
>>> referenced by leds-rt8515.c
>>>               leds/flash/leds-rt8515.o:(rt8515_probe) in archive
drivers/built-in.a

Adding 'depends on V4L2_FLASH_LED_CLASS' in Kconfig would avoid that,
but it would make it impossible to use the driver without the
v4l2 support.

Add the same dependency that the other users of this class have
instead, which just prevents the broken configuration.

Fixes: e1c6edcb ("leds: rt8515: Add Richtek RT8515 LED driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Pavel Machek <pavel@ucw.cz>

Fixes: 2cea4a7a ("scripts: use pkg-config to locate libcrypto")
Signed-off-by: Rolf Eike Beer <eb@emlix.com>
Cc: stable@vger.kernel.org # 5.6.x
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

These are NOT exported to userspace.

The headers listed in arch/sparc/include/uapi/asm/Kbuild are exported.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Pull clk fix from Stephen Boyd:
 "One small fix for the Allwinner clk driver so that display clks figure
  out the correct rate to use.

  This fixes displays running 4k@60Hz and some other resolutions that
  haven't been exercised and fully understood until now"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk: sunxi-ng: mp: fix parent rate change flag check

Pull SCSI fix from James Bottomley:
 "One fix for scsi_debug that fixes a memory leak on module removal"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: scsi_debug: Fix a memory leak

Pull cgroup fixes from Tejun Heo:
 "Two cgroup fixes:

   - fix a NULL deref when trying to poll PSI in the root cgroup

   - fix confusing controller parsing corner case when mounting cgroup
     v1 hierarchies

  And doc / maintainer file updates"

* 'for-5.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: update PSI file description in docs
  cgroup: fix psi monitor for root cgroup
  MAINTAINERS: Update my email address
  MAINTAINERS: Remove stale URLs for cpuset
  cgroup-v1: add disabled controller check in cgroup1_parse_param()

Merge fixes from Andrew Morton:
 "6 patches.

  Subsystems affected by this patch series: mm/pagemap, scripts,
  MAINTAINERS, and h8300"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  h8300: fix PREEMPTION build, TI_PRE_COUNT undefined
  MAINTAINERS: add Andrey Konovalov to KASAN reviewers
  MAINTAINERS: update Andrey Konovalov's email address
  MAINTAINERS: update KASAN file list
  scripts/recordmcount.pl: support big endian for ARCH sh
  m68k: make __pfn_to_phys() and __phys_to_pfn() available for !MMU

Pull i2c fix from Wolfram Sang:
 "One more I2C driver bugfix"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: stm32f7: fix configuration of the digital filter

Pull btrfs fix from David Sterba:
 "A regression fix caused by a refactoring in 5.11.

  A corrupted superblock wouldn't be detected by checksum verification
  due to wrongly placed initialization of the checksum length, thus
  making memcmp always work"

* tag 'for-5.11-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: initialize fs_info::csum_size earlier in open_ctree

Fix a build error for undefined 'TI_PRE_COUNT' by adding it to
asm-offsets.c.

  h8300-linux-ld: arch/h8300/kernel/entry.o: in function `resume_kernel': (.text+0x29a): undefined reference to `TI_PRE_COUNT'

Link: https://lkml.kernel.org/r/20210212021650.22740-1-rdunlap@infradead.org
Fixes: df2078b8 ("h8300: Low level entry")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add my personal email address to KASAN reviewers list.

Link: https://lkml.kernel.org/r/c1ce89a7aae0e2d6852249c280b1eb59aeac30c0.1613150186.git.andreyknvl@google.comSigned-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Use my personal email address.

Link: https://lkml.kernel.org/r/b0ec98dabbc12336c162788f5ccde97045a0d65e.1613150186.git.andreyknvl@google.comSigned-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Account for the following files:

 - lib/Kconfig.kasan

 - lib/test_kasan_module.c

 - arch/arm64/include/asm/mte-kasan.h

Link: https://lkml.kernel.org/r/7f9771d97b34d396bfdc4e288ad93486bb865a06.1613150186.git.andreyknvl@google.comSigned-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The kernel test robot reported the following issue:

    CC [M]  drivers/soc/litex/litex_soc_ctrl.o
  sh4-linux-objcopy: Unable to change endianness of input file(s)
  sh4-linux-ld: cannot find drivers/soc/litex/.tmp_gl_litex_soc_ctrl.o: No such file or directory
  sh4-linux-objcopy: 'drivers/soc/litex/.tmp_mx_litex_soc_ctrl.o': No such file

The problem is that the format of input file is elf32-shbig-linux, but
sh4-linux-objcopy wants to output a file which format is elf32-sh-linux:

  $ sh4-linux-objdump -d drivers/soc/litex/litex_soc_ctrl.o | grep format
  drivers/soc/litex/litex_soc_ctrl.o:     file format elf32-shbig-linux

Link: https://lkml.kernel.org/r/20210210150435.2171567-1-rong.a.chen@intel.com
Link: https://lore.kernel.org/linux-mm/202101261118.GbbYSlHu-lkp@intel.comSigned-off-by: Rong Chen <rong.a.chen@intel.com>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Yoshinori Sato <ysato@users.osdn.me>
Cc: Rich Felker <dalias@libc.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Recent changes that obsoleted DISCONTIGMEM on m68k switched the MMU
variant to use generic definitions of __pfn_to_phys() and __phys_to_pfn(),
but missed the !MMU variant which caused a build failure:

   drivers/media/common/videobuf2/videobuf2-dma-contig.c: In function 'vb2_dc_get_userptr':
   drivers/media/common/videobuf2/videobuf2-dma-contig.c:509:5: error: implicit declaration of function '__pfn_to_phys' [-Werror=implicit-function-declaration]
     509 |     __pfn_to_phys(nums[0]), size, buf->dma_dir, 0);
         |     ^~~~~~~~~~~~~
   cc1: some warnings being treated as errors

Enable __pfn_to_phys() and __phys_to_pfn() on !MMU builds.

Link: https://lkml.kernel.org/r/20210211232202.GS299309@linux.ibm.com
Fixes: 4bfc848e ("m68k/mm: enable use of generic memory_model.h for !DISCONTIGMEM")
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull cifs fixes from Steve French:
 "Four small smb3 fixes to the new mount API (including a particularly
  important one for DFS links).

  These were found in testing this week of additional DFS scenarios, and
  a user testing of an apache container problem"

* tag '5.11-rc7-smb3-github' of git://github.com/smfrench/smb3-kernel:
  cifs: Set CIFS_MOUNT_USE_PREFIX_PATH flag on setting cifs_sb->prepath.
  cifs: In the new mount api we get the full devname as source=
  cifs: do not disable noperm if multiuser mount option is not provided
  cifs: fix dfs-links

Pull io_uring fix from Jens Axboe:
 "Revert of a patch from this release that caused a regression"

* tag 'io_uring-5.11-2021-02-12' of git://git.kernel.dk/linux-block:
  Revert "io_uring: don't take fs for recvmsg/sendmsg"

Pull drm fixes from Dave Airlie:
 "Regular fixes for final, there is a ttm regression fix, dp-mst fix,
  one amdgpu revert, two i915 fixes, and some misc fixes for sun4i,
  xlnx, and vc4.

  All pretty quiet and don't think we have any known outstanding
  regressions.

  ttm:
   - page pool regression fix.

  dp_mst:
   - don't report un-attached ports as connected

  amdgpu:
   - blank screen fix

  i915:
   - ensure Type-C FIA is powered when initializing
   - fix overlay frontbuffer tracking

  sun4i:
   - tcon1 sync polarity fix
   - always set HDMI clock rate
   - fix H6 HDMI PHY config
   - fix H6 max frequency

  vc4:
   - fix buffer overflow

  xlnx:
   - fix memory leak"

* tag 'drm-fixes-2021-02-12' of git://anongit.freedesktop.org/drm/drm:
  drm/ttm: make sure pool pages are cleared
  drm/sun4i: dw-hdmi: Fix max. frequency for H6
  drm/sun4i: Fix H6 HDMI PHY configuration
  drm/sun4i: dw-hdmi: always set clock rate
  drm/sun4i: tcon: set sync polarity for tcon1 channel
  drm/i915: Fix overlay frontbuffer tracking
  Revert "drm/amd/display: Update NV1x SR latency values"
  drm/i915/tgl+: Make sure TypeC FIA is powered up when initializing it
  drm/dp_mst: Don't report ports connected if nothing is attached to them
  drm/xlnx: fix kmemleak by sending vblank_event in atomic_disable
  drm/vc4: hvs: Fix buffer overflow with the dlist handling

Pull tracing fix from Steven Rostedt:
 "Fix buffer overflow in trace event filter.

  It was reported that if an trace event was larger than a page and was
  filtered, that it caused memory corruption. The reason is that
  filtered events first go into a buffer to test the filter before being
  written into the ring buffer. Unfortunately, this write did not check
  the size"

* tag 'trace-v5.11-rc7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Check length before giving out the filter buffer

Pull xen fix from Juergen Gross:
 "A single fix for an issue introduced this development cycle: when
  running as a Xen guest on Arm systems the kernel will hang during
  boot"

* tag 'for-linus-5.11-rc8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  arm/xen: Don't probe xenbus as part of an early initcall

Pull RISC-V fix from Palmer Dabbelt:
 "A single fix this week: the removal of the GPIO reset method for the
  Ethernet phy on the HiFive Unleashed.

  This returns to relying on the bootloader's phy reset sequence, which
  we'll have to continue doing until we can sort out how to get the
  Linux phy driver to perform the special reset dance required for this
  phy"

* tag 'riscv-for-linus-5.11-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  Revert "dts: phy: add GPIO number and active state used for phy reset"

Pull arm64 fix from Catalin Marinas:
 "Fix PTRACE_PEEKMTETAGS access to an mmapped region before the first
  write"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: mte: Allow PTRACE_PEEKMTETAGS access to the zero page

The ptrace(PTRACE_PEEKMTETAGS) implementation checks whether the user
page has valid tags (mapped with PROT_MTE) by testing the PG_mte_tagged
page flag. If this bit is cleared, ptrace(PTRACE_PEEKMTETAGS) returns
-EIO.

A newly created (PROT_MTE) mapping points to the zero page which had its
tags zeroed during cpu_enable_mte(). If there were no prior writes to
this mapping, ptrace(PTRACE_PEEKMTETAGS) fails with -EIO since the zero
page does not have the PG_mte_tagged flag set.

Set PG_mte_tagged on the zero page when its tags are cleared during
boot. In addition, to avoid ptrace(PTRACE_PEEKMTETAGS) succeeding on
!PROT_MTE mappings pointing to the zero page, change the
__access_remote_tags() check to (vm_flags & VM_MTE) instead of
PG_mte_tagged.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Fixes: 34bfeea4 ("arm64: mte: Clear the tags when a page is mapped in user-space with PROT_MTE")
Cc: <stable@vger.kernel.org> # 5.10.x
Cc: Will Deacon <will@kernel.org>
Reported-by: Luis Machado <luis.machado@linaro.org>
Tested-by: Luis Machado <luis.machado@linaro.org>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lore.kernel.org/r/20210210180316.23654-1-catalin.marinas@arm.com

User reported that btrfs-progs misc-tests/028-superblock-recover fails:

      [TEST/misc]   028-superblock-recover
  unexpected success: mounted fs with corrupted superblock
  test failed for case 028-superblock-recover

The test case expects that a broken image with bad superblock will be
rejected to be mounted. However, the test image just passed csum check
of superblock and was successfully mounted.

Commit 55fc29be ("btrfs: use cached value of fs_info::csum_size
everywhere") replaces all calls to btrfs_super_csum_size by
fs_info::csum_size. The calls include the place where fs_info->csum_size
is not initialized. So btrfs_check_super_csum() passes because memcmp()
with len 0 always returns 0.

Fix it by caching csum size in btrfs_fs_info::csum_size once we know the
csum type in superblock is valid in open_ctree().

Link: https://github.com/kdave/btrfs-progs/issues/250
Fixes: 55fc29be ("btrfs: use cached value of fs_info::csum_size everywhere")
Signed-off-by: Su Yue <l@damenly.su>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

The digital filter related computation are present in the driver
however the programming of the filter within the IP is missing.
The maximum value for the DNF is wrong and should be 15 instead of 16.

Fixes: aeb068c5 ("i2c: i2c-stm32f7: add driver")
Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@foss.st.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

(I've pulled from a non-tag to get the ttm regression fix)
drm-misc-fixes-2021-02-10:
 * dp_mst: Don't report un-attached ports as connected
 * sun4i: tcon1 sync polarity fix; Always set HDMI clock rate; Fix
          H6 HDMI PHY config; Fix H6 max frequency
 * vc4: Fix buffer overflow
 * xlnx: Fix memory leak
 * ttm: page pool regression fix.
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/YCPo6g3gDxD3P//h@linux-uq9g

CLK_SET_RATE_PARENT flag is checked on parent clock instead of current
one. Fix that.

Fixes: 3f790433 ("clk: sunxi-ng: Adjust MP clock parent rate when allowed")
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Tested-by: Andre Heider <a.heider@gmail.com>
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Link: https://lore.kernel.org/r/20210209175900.7092-2-jernej.skrabec@siol.netAcked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

Merge tag 'drm-intel-fixes-2021-02-11' of git://anongit.freedesktop.org/drm/drm-intel into drm-fixes

drm/i915 fixes for v5.11 final:
- Ensure Type-C FIA is powered when initializing
- Fix overlay frontbuffer tracking
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/87r1lnc78t.fsf@intel.com

Merge tag 'amd-drm-fixes-5.11-2021-02-10' of https://gitlab.freedesktop.org/agd5f/linux into drm-fixes

amd-drm-fixes-5.11-2021-02-10:

amdgpu:
- Blank screen fix
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Alex Deucher <alexdeucher@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210210223508.4428-1-alexander.deucher@amd.com

Pull powerpc fix from Michael Ellerman:
 "One fix for a regression seen in io_uring, introduced by our support
  for KUAP (Kernel User Access Prevention) with the Hash MMU.

  Thanks to Aneesh Kumar K.V, and Zorro Lang"

* tag 'powerpc-5.11-8' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/kuap: Allow kernel thread to access userspace after kthread_use_mm

When filters are used by trace events, a page is allocated on each CPU and
used to copy the trace event fields to this page before writing to the ring
buffer. The reason to use the filter and not write directly into the ring
buffer is because a filter may discard the event and there's more overhead
on discarding from the ring buffer than the extra copy.

The problem here is that there is no check against the size being allocated
when using this page. If an event asks for more than a page size while being
filtered, it will get only a page, leading to the caller writing more that
what was allocated.

Check the length of the request, and if it is more than PAGE_SIZE minus the
header default back to allocating from the ring buffer directly. The ring
buffer may reject the event if its too big anyway, but it wont overflow.

Link: https://lore.kernel.org/ath10k/1612839593-2308-1-git-send-email-wgong@codeaurora.org/

Cc: stable@vger.kernel.org
Fixes: 0fc1b09f ("tracing: Use temp buffer when filtering events")
Reported-by: Wen Gong <wgong@codeaurora.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Pull gpio fixes from Bartosz Golaszewski:
 "This is hopefully the last batch of fixes for this release cycle. We
  have a minor fix for a Kconfig regression as well as fixes for older
  bugs in gpio-ep93xx:

   - don't build gpio-mxs unconditionally with COMPILE_TEST enabled

   - fix two problems with interrupt handling in gpio-ep93xx"

* tag 'gpio-fixes-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux:
  gpio: ep93xx: Fix single irqchip with multi gpiochips
  gpio: ep93xx: fix BUG_ON port F usage
  gpio: mxs: GPIO_MXS should not default to y unconditionally

Stephen Rothwell reported a build error on ppc64 when
CONFIG_TRIM_UNUSED_KSYMS is enabled.

Jessica Yu pointed out the cause of the error with the reference to the
ppc64 ELF ABI:
  "Symbol names with a dot (.) prefix are reserved for holding entry
   point addresses. The value of a symbol named ".FN", if it exists,
   is the entry point of the function "FN".

As it turned out, CONFIG_TRIM_UNUSED_KSYMS has never worked for ppc64,
but this issue has been unnoticed until recently because this option
depends on !UNUSED_SYMBOLS hence is disabled by all{mod,yes}config.
(Then, it was uncovered by another patch removing UNUSED_SYMBOLS.)

Removing the dot prefix in scripts/gen_autoksyms.sh fixes the issue.
Please note it must be done before 'sort -u' because modules have
both ._mcount and _mcount undefined when CONFIG_FUNCTION_TRACER=y.

Link: https://lore.kernel.org/lkml/20210209210843.3af66662@canb.auug.org.au/Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Jessica Yu <jeyu@kernel.org>