rt2x00: Fix memleak in tx() path

When the tx() handler runs while the device has disapeared,
we did return NETDEV_TX_OK but didn't free the skb.
Signed-off-by: NIvo van Doorn <IvDoorn@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2x00mac.c

@@ -93,6 +93,7 @@ int rt2x00mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb,
 	 */
 	if (!test_bit(DEVICE_PRESENT, &rt2x00dev->flags)) {
 		ieee80211_stop_queues(hw);
+		dev_kfree_skb_any(skb);
 		return NETDEV_TX_OK;
 	}