drm/amdgpu: do not register df_mca interrupt in certain config

df/mca ras is not managed by gpu driver when gpu
is connected to cpu through xgmi. gpu driver should
register x86 mca notifier for umc ras error
notification

Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Dennis Li <Dennis.Li@amd.com>
Reviewed-by: John Clements <John.Clements@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>