zd1211: Use skb_queue_walk() instead of by-hand implementation.

Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/wireless/zd1211rw/zd_mac.c

@@ -611,7 +611,7 @@ static int filter_ack(struct ieee80211_hw *hw, struct ieee80211_hdr *rx_hdr,
 
 	q = &zd_hw_mac(hw)->ack_wait_queue;
 	spin_lock_irqsave(&q->lock, flags);
-	for (skb = q->next; skb != (struct sk_buff *)q; skb = skb->next) {
+	skb_queue_walk(q, skb) {
 		struct ieee80211_hdr *tx_hdr;
 
 		tx_hdr = (struct ieee80211_hdr *)skb->data;