drm/amdgpu: sdma v5_2 ring bo mem leak

invoke amdgpu_ring_fini for each sdma instance
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Wenhui Sheng <Wenhui.Sheng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/sdma_v5_2.c

@@ -1244,6 +1244,10 @@ static int sdma_v5_2_sw_init(void *handle)
 static int sdma_v5_2_sw_fini(void *handle)
 {
 	struct amdgpu_device *adev = (struct amdgpu_device *)handle;
+	int i;
+
+	for (i = 0; i < adev->sdma.num_instances; i++)
+		amdgpu_ring_fini(&adev->sdma.instance[i].ring);
 
 	sdma_v5_2_destroy_inst_ctx(adev);