linux-imx

drm/amdgpu: enable UVD VM only on polaris

Stoney support it, but doesn't has unlimited session support.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Leo Liu <leo.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>