drm/amdgpu: fix ring debugfs bug

debugfs file added but not released after driver unloaded

Signed-off-by: Monk Liu <Monk.Liu@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2 files changed