[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>

net/irda/irlap.c

@@ -445,9 +445,8 @@ void irlap_disconnect_request(struct irlap_cb *self)
 	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 
 	/* Don't disconnect until all data frames are successfully sent */
-	if (skb_queue_len(&self->txq) > 0) {
+	if (!skb_queue_empty(&self->txq)) {
 		self->disconnect_pending = TRUE;
-
 		return;
 	}