drm/amd/display: Change MPC Tree visual confirm colours

[Why]
MPC background colours that use fractional components look different if
MPC OGAM is in use vs in bypass mode. The current red and orange colours
look very similar when OGAM is in bypass, so the colours need to change
to be consistently very easy to tell apart.

[How]
Use colours that only have 0 or MAX values in each component

Reviewed-by: Alvin Lee <alvin.lee2@amd.com>
Signed-off-by: Joshua Aberback <joshua.aberback@amd.com>
Signed-off-by: Tom Chung <chiahsuan.chung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>