bluetooth rfcomm tty: destroy before tty_close()

rfcomm dev could be deleted in tty_hangup, so we must not call
rfcomm_dev_del again to prevent from destroying rfcomm dev before tty
close.

Signed-off-by: Dave Young <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/bluetooth/rfcomm/tty.c

···
 	if (dev->tty)
 		tty_vhangup(dev->tty);
 
-	rfcomm_dev_del(dev);
+	if (!test_bit(RFCOMM_RELEASE_ONHUP, &dev->flags))
+		rfcomm_dev_del(dev);
 	rfcomm_dev_put(dev);
 	return 0;
 }