p54: Use skb_peek_tail() instead of direct head pointer accesses.

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

drivers/net/wireless/intersil/p54/txrx.c

@@ -121,8 +121,8 @@ static int p54_assign_address(struct p54_common *priv, struct sk_buff *skb)
 	}
 	if (unlikely(!target_skb)) {
 		if (priv->rx_end - last_addr >= len) {
-			target_skb = priv->tx_queue.prev;
-			if (!skb_queue_empty(&priv->tx_queue)) {
+			target_skb = skb_peek_tail(&priv->tx_queue);
+			if (target_skb) {
 				info = IEEE80211_SKB_CB(target_skb);
 				range = (void *)info->rate_driver_data;
 				target_addr = range->end_addr;