Merge branch 'generic-zpos-v8' of http://git.linaro.org/people/benjamin.gaignard...

Merge generic ZPOS property support, this was backed up behind some other
changes I didn't have a stable branch point for. Now they are merged to Linus
tree this pull is just drm patches.

* 'generic-zpos-v8' of http://git.linaro.org/people/benjamin.gaignard/kernel:
  drm: rcar: use generic code for managing zpos plane property
  drm/exynos: use generic code for managing zpos plane property
  drm: sti: use generic zpos for plane
  drm: add generic zpos property