drm/amd/display: create DCN3-specific log for MPC state

Logging DCN3 MPC state was following DCN1 implementation that doesn't
consider new DCN3 MPC color blocks. Create new elements according to
DCN3 MPC color caps and a new DCN3-specific function for reading MPC
data.

v3:
- remove gamut remap reg reading in favor of fixed31_32 matrix data

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