drm/amd/display: Fix cursor visual confirm update

[Why/How]
Certain transitions from HW to SW cursor can be missed, which will
result in black visual confirm instead of expected blue/red. Need to add
handling for cursor visual confirm to dc_update_visual_confirm_color.

Reviewed-by: Alvin Lee <alvin.lee2@amd.com>
Signed-off-by: Ilya Bakoulin <Ilya.Bakoulin@amd.com>
Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>