drm/amdgpu: move VM manager clean into the VM code again

It's not a good idea to duplicate that code.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chunming Zhou <davdi1.zhou@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
4 files changed