wifi: mac80211: fix possible leak in ieee80211_tx_control_port()

Add missing dev_kfree_skb() in an error path in
ieee80211_tx_control_port() to avoid a memory leak.

Fixes: dd820ed6 ("wifi: mac80211: return error from control port TX for drops")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20220818043349.4168835-1-yangyingliang@huawei.comSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/tx.c

@@ -5885,6 +5885,7 @@ int ieee80211_tx_control_port(struct wiphy *wiphy, struct net_device *dev,
 	rcu_read_lock();
 	err = ieee80211_lookup_ra_sta(sdata, skb, &sta);
 	if (err) {
+		dev_kfree_skb(skb);
 		rcu_read_unlock();
 		return err;
 	}