x86/acpi: Support objtool validation in wakeup_64.S

The OBJECT_FILES_NON_STANDARD annotation is used to tell objtool to
ignore a file.  File-level ignores won't work when validating vmlinux.o.

Instead, tell objtool to ignore do_suspend_lowlevel() directly with the
STACK_FRAME_NON_STANDARD annotation.

Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/269eda576c53bc9ecc8167c211989111013a67aa.1611263462.git.jpoimboe@redhat.com

arch/x86/kernel/acpi/Makefile

 # SPDX-License-Identifier: GPL-2.0
-OBJECT_FILES_NON_STANDARD_wakeup_$(BITS).o := y
 
 obj-$(CONFIG_ACPI)		+= boot.o
 obj-$(CONFIG_ACPI_SLEEP)	+= sleep.o wakeup_$(BITS).o

arch/x86/kernel/acpi/wakeup_64.S

 /* SPDX-License-Identifier: GPL-2.0-only */
 .text
 #include <linux/linkage.h>
+#include <linux/objtool.h>
 #include <asm/segment.h>
 #include <asm/pgtable_types.h>
 #include <asm/page_types.h>
@@ -128,6 +129,7 @@ SYM_FUNC_START(do_suspend_lowlevel)
 	FRAME_END
 	jmp	restore_processor_state
 SYM_FUNC_END(do_suspend_lowlevel)
+STACK_FRAME_NON_STANDARD do_suspend_lowlevel
 
 .data
 saved_rbp:		.quad	0