wifi: mac80211: free skb on error path in ieee80211_beacon_get_ap()

In 'ieee80211_beacon_get_ap()', free allocated skb in case of error
returned by 'ieee80211_beacon_protect()'. Compile tested only.
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Link: https://patch.msgid.link/20240805142035.227847-1-dmantipov@yandex.ruSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/tx.c

@@ -5348,8 +5348,10 @@ ieee80211_beacon_get_ap(struct ieee80211_hw *hw,
 	if (beacon->tail)
 		skb_put_data(skb, beacon->tail, beacon->tail_len);
 
-	if (ieee80211_beacon_protect(skb, local, sdata, link) < 0)
+	if (ieee80211_beacon_protect(skb, local, sdata, link) < 0) {
+		dev_kfree_skb(skb);
 		return NULL;
+	}
 
 	ieee80211_beacon_get_finish(hw, vif, link, offs, beacon, skb,
 				    chanctx_conf, csa_off_base);