Merge tag 'drm-vc4-next-2016-05-02' of https://github.com/anholt/linux into drm-next

Merge tag 'drm-vc4-next-2016-05-02' of https://github.com/anholt/linux into drm-next

This pull request brings in DPI panel support, gamma ramp support, and
render nodes for vc4.

* tag 'drm-vc4-next-2016-05-02' of https://github.com/anholt/linux:
  drm/vc4: Add missing render node support
  drm/vc4: Add support for gamma ramps.
  drm/vc4: Fix NULL deref in HDMI init error path
  drm/vc4: Add DPI driver
  drm: Add an encoder and connector type enum for DPI.