drm/amd/display: Add visual confirm color support for MCLK switch

[Why && How]
We would like to have visual confirm color support for MCLK switch.
	1. Set visual confirm color to yellow: Vblank MCLK switch.
	2. Set visual confirm color to cyan: FPO + Vblank MCLK
	switch.
	3. Set visual confirm color to pink: Vactive MCLK switch.

Reviewed-by: Jun Lei <jun.lei@amd.com>
Acked-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Leo (Hanghong) Ma <hanghong.ma@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>