drm/amd/display: Refactor to move gamma correction to module

Refactor part 4 - Moving input gamma correction programming into color module

DM will translate to dc_gamma structure, but programming will be moved into
the color module. Later, this will allow gamma correction to be added on top of
in/out transfer function curves.

Signed-off-by: Anthony Koo <anthony.koo@amd.com>
Reviewed-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>