drm/amd/display: Implement color management

Implement color management functionalities within amdgpu_dm_color, and
expose functions within amdgpu_dm.h.

Signed-off-by: Leo (Sunpeng) Li <sunpeng.li@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>