wifi: mac80211: fix potential deadlock in ieee80211_key_link()

Add the missing unlock before return in the error handling case.

Fixes: ccdde7c7 ("wifi: mac80211: properly implement MLO key handling")
Signed-off-by: Sun Ke <sunke32@huawei.com>
Link: https://lore.kernel.org/r/20220827022452.823381-1-sunke32@huawei.comSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/key.c

@@ -865,8 +865,10 @@ int ieee80211_key_link(struct ieee80211_key *key,
 		if (link_id >= 0) {
 			link_sta = rcu_dereference_protected(sta->link[link_id],
 							     lockdep_is_held(&sta->local->sta_mtx));
-			if (!link_sta)
-				return -ENOLINK;
+			if (!link_sta) {
+				ret = -ENOLINK;
+				goto out;
+			}
 		}
 
 		old_key = key_mtx_dereference(sdata->local, link_sta->gtk[idx]);