For virtual display feature, when the GPU has DCE engine, need to disable
the VGA render and CRTC, or it will hang when initialize GMC.
Signed-off-by: Emily Deng <Emily.Deng@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>