drm/amdgpu: cleanup amdgpu_ring_fini

cleanup amdgpu_ring_fini to check the prerequisites before changing ring->sched.ready
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/amdgpu_ring.c

@@ -351,12 +351,13 @@ int amdgpu_ring_init(struct amdgpu_device *adev, struct amdgpu_ring *ring,
  */
 void amdgpu_ring_fini(struct amdgpu_ring *ring)
 {
-	ring->sched.ready = false;
 
 	/* Not to finish a ring which is not initialized */
 	if (!(ring->adev) || !(ring->adev->rings[ring->idx]))
 		return;
 
+	ring->sched.ready = false;
+
 	amdgpu_device_wb_free(ring->adev, ring->rptr_offs);
 	amdgpu_device_wb_free(ring->adev, ring->wptr_offs);