drm/amdgpu/vcn: Update vcn.cur_state during suspend

Replace vcn_v1_0_stop with vcn_v1_0_set_powergating_state during suspend,
to keep adev->vcn.cur_state update. It will fix VCN S3 hung issue.
Signed-off-by: James Zhu <James.Zhu@amd.com>
Reviewed-by: Leo Liu <leo.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/vcn_v1_0.c

@@ -48,6 +48,7 @@ static void vcn_v1_0_set_enc_ring_funcs(struct amdgpu_device *adev);
 static void vcn_v1_0_set_jpeg_ring_funcs(struct amdgpu_device *adev);
 static void vcn_v1_0_set_irq_funcs(struct amdgpu_device *adev);
 static void vcn_v1_0_jpeg_ring_set_patch_ring(struct amdgpu_ring *ring, uint32_t ptr);
+static int vcn_v1_0_set_powergating_state(void *handle, enum amd_powergating_state state);
 
 /**
  * vcn_v1_0_early_init - set function pointers
@@ -214,7 +215,7 @@ static int vcn_v1_0_hw_fini(void *handle)
 	struct amdgpu_ring *ring = &adev->vcn.ring_dec;
 
 	if (RREG32_SOC15(VCN, 0, mmUVD_STATUS))
-		vcn_v1_0_stop(adev);
+		vcn_v1_0_set_powergating_state(adev, AMD_PG_STATE_GATE);
 
 	ring->sched.ready = false;