wl12xx: use ieee80211_free_txskb()

Use the newly introduced ieee80211_free_txskb() instead
of dev_kfree_skb() for failed tx packets.

Additionally, if the skb is a dummy packet, re-enqueue
it (as the fw expects it) instead of freeing it.
Reported-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>

drivers/net/wireless/wl12xx/main.c

@@ -1448,7 +1448,7 @@ static void wl1271_op_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 	if (hlid == WL12XX_INVALID_LINK_ID ||
 	    (wlvif && !test_bit(hlid, wlvif->links_map))) {
 		wl1271_debug(DEBUG_TX, "DROP skb hlid %d q %d", hlid, q);
-		dev_kfree_skb(skb);
+		ieee80211_free_txskb(hw, skb);
 		goto out;
 	}
 

drivers/net/wireless/wl12xx/tx.c

@@ -740,7 +740,14 @@ void wl1271_tx_work_locked(struct wl1271 *wl)
 			set_bit(WL1271_FLAG_FW_TX_BUSY, &wl->flags);
 			goto out_ack;
 		} else if (ret < 0) {
-			dev_kfree_skb(skb);
+			if (wl12xx_is_dummy_packet(wl, skb))
+				/*
+				 * fw still expects dummy packet,
+				 * so re-enqueue it
+				 */
+				wl1271_skb_queue_head(wl, wlvif, skb);
+			else
+				ieee80211_free_txskb(wl->hw, skb);
 			goto out_ack;
 		}
 		buf_offset += ret;