Bluetooth: add debug output to l2cap_ack_timeout()

Acked-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NGustavo F. Padovan <padovan@profusion.mobi>

net/bluetooth/l2cap_core.c

@@ -1985,6 +1985,8 @@ static void l2cap_ack_timeout(struct work_struct *work)
 	struct l2cap_chan *chan = container_of(work, struct l2cap_chan,
 							ack_timer.work);
 
+	BT_DBG("chan %p", chan);
+
 	lock_sock(chan->sk);
 	l2cap_send_ack(chan);
 	release_sock(chan->sk);