BugLink: http://bugs.launchpad.net/bugs/1599109

Sync i915_bpo with v4.7-rc6. Revert a bunch of commits from it to let it build
without pulling a ton of core drm changes.

3ed605bc kernel.h: add u64_to_user_ptr()
2347aa7c drm: i915: Explicitly apply PWM config extracted from pwm_args
0552f765 drm/i915/mst: use reference counted connectors. (v3)
8863dc7f drm/i915: Correctly refcount connectors in hw state readou"
ec2dc6a0 drm: Drop crtc argument from __drm_atomic_helper_crtc_destroy_state
80a89a5e drm/i915: make i915_gem_mmap_ioctl wait for mmap_sem killable
e87666b5 drm/i915/shrinker: Hook up vmap allocation failure notifier
168cf367 drm/i915/shrinker: Refactor common uninterruptible locking
eae2c43b drm/i915/shrinker: Restrict vmap purge to objects with vmaps
1768d455 drm/i915/shrinker: Report "unevictable" pages
1bec9b0b drm/i915/shrinker: Only shmemfs objects are backed by swap
747a598f drm/mode: introduce wrapper to read framebuffer refcount.
1d2ac403 drm: Protect dev->filelist with its own mutex
cab10327 drm/i915: Fix missing unlock on error in i915_ppgtt_info()
a8ad0bd8 drm: Remove unused drm_device from drm_gem_object_lookup()
Signed-off-by: Timo Aaltonen <timo.aaltonen@canonical.com>
Acked-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>