drm/amdgpu/vcn2.5: add cancel_delayed_work_sync before power gate

Add cancel_delayed_work_sync before set power gating state
to avoid race condition issue when power gating.
Signed-off-by: James Zhu <James.Zhu@amd.com>
Reviewed-by: Leo Liu <leo.liu@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

drivers/gpu/drm/amd/amdgpu/vcn_v2_5.c

@@ -321,6 +321,8 @@ static int vcn_v2_5_hw_fini(void *handle)
 	struct amdgpu_device *adev = (struct amdgpu_device *)handle;
 	int i;
 
+	cancel_delayed_work_sync(&adev->vcn.idle_work);
+
 	for (i = 0; i < adev->vcn.num_vcn_inst; ++i) {
 		if (adev->vcn.harvest_config & (1 << i))
 			continue;