drm/amd/display: decouple color state from hw state log

Prepare to hook up color state log according to the DCN version.

v3:
- put functions in single line (Siqueira)

Signed-off-by: Melissa Wen <mwen@igalia.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>