[NET]: Transform skb_queue_len() binary tests into skb_queue_empty()

This is part of the grand scheme to eliminate the qlen
member of skb_queue_head, and subsequently remove the
'list' member of sk_buff.

Most users of skb_queue_len() want to know if the queue is
empty or not, and that's trivially done with skb_queue_empty()
which doesn't use the skb_queue_head->qlen member and instead
uses the queue list emptyness as the test.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c
index f3f6355..63a123c 100644
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -590,8 +590,11 @@
 	for (;;) {
 		set_current_state(TASK_INTERRUPTIBLE);
 
-		if (skb_queue_len(&sk->sk_receive_queue) || sk->sk_err || (sk->sk_shutdown & RCV_SHUTDOWN) ||
-				signal_pending(current) || !timeo)
+		if (!skb_queue_empty(&sk->sk_receive_queue) ||
+		    sk->sk_err ||
+		    (sk->sk_shutdown & RCV_SHUTDOWN) ||
+		    signal_pending(current) ||
+		    !timeo)
 			break;
 
 		set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);