[Intel-gfx] [RFC] Updated DRM plane handling patches

[Jesse Barnes]

This patchset updates the previous one, incorporating the feedback I
received:
  1) uses the v4l fourcc codes to communicate pixel format
  2) adds a new addfb ioctl that takes a format
  3) adds working SNB support for the new code

Comments welcome.  I'll be pushing intel-gpu-tools testdisplay support
for this shortly if people want to play around with it.  Next step is to
incorporate it into X and Wayland to see if the API is rich enough for
our needs.

Thanks,
Jesse