drm/amd/display: Hardware cursor changes color when switched to software cursor

[Why & How]
DCN4 Cursor has separate degamma block and should always
do Cursor degamma for Cursor color modes.

Reviewed-by: Chris Park <chris.park@amd.com>
Signed-off-by: Nevenko Stupar <Nevenko.Stupar@amd.com>
Signed-off-by: Roman Li <roman.li@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>