Merge branch 'drm-fb-helper' of git://people.freedesktop.org/~danvet/drm into drm...

This is the drm fb helper cleanup, mostly motivated by strange things I've
seen in my locking rework and the i915 modeset revamp. Compared to the
original submission I've reinstated the setup flexibility you'd like to
retain, kerneldoc has been reviewed by Laurent Pinchart and Rob Clark
reviewed the code changes.

Quick overview of the changes:
- Cleaned-up library interface for drivers using the fb helper, also
  simplified the fb allocation callback since no driver supported
  reallocating the fb on-the-fly. And the fbdev/fbcon code keeps pointers
  to the old mapping around anyway, so reallocating backing storage will
  be much more work.
- No longer call the crtc helper "disable everything" function at init
  time, but allow drivers to do so. Motivated by i915's fastboot effort
  and allows us to drop a bunch of noop dummy functions just to avoid
  calling NULL function pointers from i915.ko.
- Properly clear old state when doing modeset calls, the fb helper left
  some old modes in there and unconditionally set an fb (even when
  disabling a crtc). The crtc helpers didn't care, but i915 modeset code
  can now drop a few special cases.
- Full kerneldoc for the fb helper. Yay!
- My version of the "don't sleep in panic ->unblank calls". The patch is
  already in -mm, I guess Andrew can drop it as soon as this pull lands in
  drm-next.

* 'drm-fb-helper' of git://people.freedesktop.org/~danvet/drm:
  drm/fb-helper: remove unused members of struct drm_fb_helper
  drm/fb-helper: don't sleep for screen unblank when an oopps is in progress
  drm/fb-helper: improve kerneldoc
  drm/<drivers>: simplify ->fb_probe callback
  drm/fb-helper: streamline drm_fb_helper_single_fb_probe
  drm/fb-helper: directly call set_par from the hotplug handler
  drm/fb-helper: fixup set_config semantics
  drm/i915: rip out helper->disable noop functions
  drm/fb-helper: don't disable everything in initial_config
  drm/tegra: don't set up initial fbcon config twice
  drm/fb-helper: unexport drm_fb_helper_single_fb_probe
  drm/fb-helper: unexport drm_fb_helper_panic
  drm/fb-helper: kill drm_fb_helper_restore
  drm: review locking for drm_fb_helper_restore_fbdev_mode