[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/drivers/isdn/icn/icn.c b/drivers/isdn/icn/icn.c
index 9fc0c1e..e0d1b01 100644
--- a/drivers/isdn/icn/icn.c
+++ b/drivers/isdn/icn/icn.c
@@ -304,12 +304,12 @@
 	isdn_ctrl cmd;
 
 	if (!(card->sndcount[channel] || card->xskb[channel] ||
-	      skb_queue_len(&card->spqueue[channel])))
+	      !skb_queue_empty(&card->spqueue[channel])))
 		return;
 	if (icn_trymaplock_channel(card, mch)) {
 		while (sbfree && 
 		       (card->sndcount[channel] ||
-			skb_queue_len(&card->spqueue[channel]) ||
+			!skb_queue_empty(&card->spqueue[channel]) ||
 			card->xskb[channel])) {
 			spin_lock_irqsave(&card->lock, flags);
 			if (card->xmit_lock[channel]) {