drm/amd/display: Added visual confirm for DCC

drm/amd/display: Added visual confirm for DCC

[WHY]
We want to add a visual confirm mode for DCC and MCache for
debugging purpose.

[HOW]
color pipes based on whether DCC is enabled and what MCache id
is used.
black - DCC disabled
red - DCC enabled
grey - 2 different MCaches used
other colors - 1 MCache used

Reviewed-by: Dillon Varone <dillon.varone@amd.com>
Signed-off-by: Leo Zeng <Leo.Zeng@amd.com>
Signed-off-by: Wayne Lin <wayne.lin@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>