drm/amd/display: Remove program_csc_matrix

[Why] On DCN1/DCE, There are two functions programming OCSC:
program_csc_matrix and program_output_csc. They do the same thing.

[How] Consolidate to use only program_output_csc.

Signed-off-by: Krunoslav Kovac <Krunoslav.Kovac@amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>