Bluetooth: Fix crash when ioctl(HCIUARTSETPROTO) fails

If the fail happens the HCI del_timer may timeout after the the hci dev
unregister. This lead to a kernel crash.

Reported-by: Vinicius Costa Gomes <vinicius.gomes@openbossa.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

net/bluetooth/hci_core.c

@@ -1199,6 +1199,8 @@ int hci_unregister_dev(struct hci_dev *hdev)
 
 	hci_unregister_sysfs(hdev);
 
+	hci_del_off_timer(hdev);
+
 	destroy_workqueue(hdev->workqueue);
 
 	hci_dev_lock_bh(hdev);