drm/amdgpu/vcn3: 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>

drivers/gpu/drm/amd/amdgpu/vcn_v3_0.c

@@ -380,15 +380,14 @@ static int vcn_v3_0_hw_init(void *handle)
 static int vcn_v3_0_hw_fini(void *handle)
 {
 	struct amdgpu_device *adev = (struct amdgpu_device *)handle;
-	struct amdgpu_ring *ring;
 	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;
 
-		ring = &adev->vcn.inst[i].ring_dec;
-
 		if (!amdgpu_sriov_vf(adev)) {
 			if ((adev->pg_flags & AMD_PG_SUPPORT_VCN_DPG) ||
 					(adev->vcn.cur_state != AMD_PG_STATE_GATE &&