vfio-ccw: Destroy kmem cache region on module exit

Free the vfio_ccw_cmd_region on module exit.

Fixes: d5afd5d1 ("vfio-ccw: add handling for async channel instructions")
Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
Message-Id: <c0f39039d28af39ea2939391bf005e3495d890fd.1559576250.git.alifm@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

drivers/s390/cio/vfio_ccw_drv.c

@@ -299,6 +299,7 @@ static void __exit vfio_ccw_sch_exit(void)
 	css_driver_unregister(&vfio_ccw_sch_driver);
 	isc_unregister(VFIO_CCW_ISC);
 	kmem_cache_destroy(vfio_ccw_io_region);
+	kmem_cache_destroy(vfio_ccw_cmd_region);
 	destroy_workqueue(vfio_ccw_work_q);
 }
 module_init(vfio_ccw_sch_init);