For DCC we will use 2/3 planes to avoid X rendering to the frontbuffer
with DCC compressed images. To make this work with the core KMS
validation we need to add extra formats with the extra planes.

However, due to flexibility we set bpp = 0 for the extra planes and
do the validation ourselves.
Signed-off-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>