Bluetooth: Refactor l2cap_retransmit_frame()

Make the code flow cleaner and changes the function to void.
It also fixes a potential NULL dereference with skb.
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
Reviewed-by: João Paulo Rechi Vita <jprvita@profusion.mobi>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/l2cap.c

@@ -1331,25 +1331,29 @@ static int l2cap_streaming_send(struct sock *sk)
 	return 0;
 }
 
-static int l2cap_retransmit_frame(struct sock *sk, u8 tx_seq)
+static void l2cap_retransmit_frame(struct sock *sk, u8 tx_seq)
 {
 	struct l2cap_pinfo *pi = l2cap_pi(sk);
 	struct sk_buff *skb, *tx_skb;
 	u16 control, fcs;
 
 	skb = skb_peek(TX_QUEUE(sk));
+	if (!skb)
+		return;
+
 	do {
-		if (bt_cb(skb)->tx_seq != tx_seq) {
-			if (skb_queue_is_last(TX_QUEUE(sk), skb))
+		if (bt_cb(skb)->tx_seq == tx_seq)
 			break;
-			skb = skb_queue_next(TX_QUEUE(sk), skb);
-			continue;
-		}
+
+		if (skb_queue_is_last(TX_QUEUE(sk), skb))
+			return;
+
+	} while ((skb = skb_queue_next(TX_QUEUE(sk), skb)));
 
 	if (pi->remote_max_tx &&
 			bt_cb(skb)->retries == pi->remote_max_tx) {
 		l2cap_send_disconn_req(pi->conn, sk);
-			break;
+		return;
 	}
 
 	tx_skb = skb_clone(skb, GFP_ATOMIC);
@@ -1365,9 +1369,6 @@ static int l2cap_retransmit_frame(struct sock *sk, u8 tx_seq)
 	}
 
 	l2cap_do_send(sk, tx_skb);
-		break;
-	} while(1);
-	return 0;
 }
 
 static int l2cap_ertm_send(struct sock *sk)