drm/amdgpu: make sure we unpin the UVD BO

Releasing pinned BOs is illegal now. UVD 6 was missing from:
commit 2f40801d ("drm/amdgpu: make sure we unpin the UVD BO")

Fixes: 2f40801d ("drm/amdgpu: make sure we unpin the UVD BO")
Cc: stable@vger.kernel.org
Signed-off-by: Nirmoy Das <nirmoy.das@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/uvd_v6_0.c

@@ -357,6 +357,7 @@ static int uvd_v6_0_enc_ring_test_ib(struct amdgpu_ring *ring, long timeout)
 
 error:
 	dma_fence_put(fence);
+	amdgpu_bo_unpin(bo);
 	amdgpu_bo_unreserve(bo);
 	amdgpu_bo_unref(&bo);
 	return r;