In XGMI configuration, the FB region covers vram region from peer
device, adjust system aperture to cover all of them
Signed-off-by: Le Ma <le.ma@amd.com>
Reviewed-by: Feifei Xu <Feifei.Xu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>