rtl8180: use cached queue mapping for skb in rtl8180_tx

Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rtl818x/rtl8180_dev.c

@@ -296,7 +296,7 @@ static int rtl8180_tx(struct ieee80211_hw *dev, struct sk_buff *skb)
 	entry->flags = cpu_to_le32(tx_flags);
 	__skb_queue_tail(&ring->queue, skb);
 	if (ring->entries - skb_queue_len(&ring->queue) < 2)
-		ieee80211_stop_queue(dev, skb_get_queue_mapping(skb));
+		ieee80211_stop_queue(dev, prio);
 	spin_unlock_irqrestore(&priv->lock, flags);
 
 	rtl818x_iowrite8(priv, &priv->map->TX_DMA_POLLING, (1 << (prio + 4)));