[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/net/wireless/airo.c b/drivers/net/wireless/airo.c
index c12648d..47f3c5d 100644
--- a/drivers/net/wireless/airo.c
+++ b/drivers/net/wireless/airo.c
@@ -2374,7 +2374,7 @@
 	/*
 	 * Clean out tx queue
 	 */
-	if (test_bit(FLAG_MPI, &ai->flags) && skb_queue_len (&ai->txq) > 0) {
+	if (test_bit(FLAG_MPI, &ai->flags) && !skb_queue_empty(&ai->txq)) {
 		struct sk_buff *skb = NULL;
 		for (;(skb = skb_dequeue(&ai->txq));)
 			dev_kfree_skb(skb);
@@ -3287,7 +3287,7 @@
 				if (status & EV_TXEXC)
 					get_tx_error(apriv, -1);
 				spin_lock_irqsave(&apriv->aux_lock, flags);
-				if (skb_queue_len (&apriv->txq)) {
+				if (!skb_queue_empty(&apriv->txq)) {
 					spin_unlock_irqrestore(&apriv->aux_lock,flags);
 					mpi_send_packet (dev);
 				} else {