[Why]
We need DC's color space to match the color encoding and color space
specified by userspace to correctly render YUV surfaces.

[How]
Add the DRM color properties when the DC plane supports NV12.
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Sun peng Li <Sunpeng.Li@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>