mac80211: Remove a redundant mutex unlock

The below-mentioned commit changed the code to unlock *inside*
the function, but previously the unlock was *outside*. It failed
to remove the outer unlock, however, leading to double unlock.

Fix this.

Fixes: 33483a6b ("mac80211: fix missing unlock on error in ieee80211_mark_sta_auth()")
Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Link: https://lore.kernel.org/r/20200221104719.cce4741cf6eb.I671567b185c8a4c2409377e483fd149ce590f56d@changeid
[rewrite commit message to better explain what happened]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/mlme.c

@@ -2959,7 +2959,7 @@ static void ieee80211_rx_mgmt_auth(struct ieee80211_sub_if_data *sdata,
 	    (auth_transaction == 2 &&
 	     ifmgd->auth_data->expected_transaction == 2)) {
 		if (!ieee80211_mark_sta_auth(sdata, bssid))
-			goto out_err;
+			return; /* ignore frame -- wait for timeout */
 	} else if (ifmgd->auth_data->algorithm == WLAN_AUTH_SAE &&
 		   auth_transaction == 2) {
 		sdata_info(sdata, "SAE peer confirmed\n");
@@ -2967,10 +2967,6 @@ static void ieee80211_rx_mgmt_auth(struct ieee80211_sub_if_data *sdata,
 	}
 
 	cfg80211_rx_mlme_mgmt(sdata->dev, (u8 *)mgmt, len);
-	return;
- out_err:
-	mutex_unlock(&sdata->local->sta_mtx);
-	/* ignore frame -- wait for timeout */
 }
 
 #define case_WLAN(type) \