V4L/DVB (13067): radio-mr800: fix potential use after free

Fix portential use after free.
Signed-off-by: NDavid Ellingsworth <david@identd.dyndns.org>
Acked-by: NAlexey Klimov <klimov.linux@gmail.com>
Signed-off-by: NDouglas Schilling Landgraf <dougsland@redhat.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/radio/radio-mr800.c

@@ -273,8 +273,8 @@ static void usb_amradio_disconnect(struct usb_interface *intf)
 	mutex_unlock(&radio->lock);
 
 	usb_set_intfdata(intf, NULL);
-	video_unregister_device(&radio->videodev);
 	v4l2_device_disconnect(&radio->v4l2_dev);
+	video_unregister_device(&radio->videodev);
 }
 
 /* vidioc_querycap - query device capabilities */