Misc drm patches with mostly polish patches from Thierry, with a bit of
generic mode validation from Ville and a few other oddball things.

* tag 'topic/core-stuff-2014-12-19' of git://anongit.freedesktop.org/drm-intel: (25 commits)
  drm: Include drm_crtc_helper.h in DocBook
  drm: Make drm_crtc_helper.h standalone includible
  drm: Move IRQ related fields to proper section
  drm: Remove stale comment
  drm: Do basic sanity checks for user modes
  drm: Perform basic sanity checks on probed modes
  drm: Reorganize probed mode validation
  drm/doc: Remove duplicate "by"
  drm/info: Remove unused code
  drm/cache: Use wbinvd helpers
  drm/plane-helper: Test for plane disable earlier
  drm/doc: Document drm_add_modes_noedid() usage
  drm: bit of spell-check / editorializing.
  drm: Prefer sizeof(type) over sizeof type
  drm: Remove useless else block
  drm: Remove unneeded braces for single statement blocks
  drm: Do not assign in if condition
  drm: Prefer kmalloc_array() over kmalloc() with multiply
  drm: Prefer kcalloc() over kzalloc() with multiply
  drm: Miscellaneous checkpatch whitespace cleanups
  ...