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>
diff --git a/drivers/net/wireless/wl12xx/main.c b/drivers/net/wireless/wl12xx/main.c
index 2f7bfa8..333bc29 100644
--- a/drivers/net/wireless/wl12xx/main.c
+++ b/drivers/net/wireless/wl12xx/main.c
@@ -1448,7 +1448,7 @@
 	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;
 	}