mac80211: don't call conf_tx under RCU lock

Reinette pointed out that with the sta_info RCU-ification
the behaviour here changed and the conf_tx callback is
now invoked under RCU read lock. That is not necessary so
this patch restores the original behaviour

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Tested-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/ieee80211_sta.c

@@ -1930,16 +1930,16 @@ static void ieee80211_rx_mgmt_assoc_resp(struct ieee80211_sub_if_data *sdata,
 
 	if (elems.wmm_param && (ifsta->flags & IEEE80211_STA_WMM_ENABLED)) {
 		sta->flags |= WLAN_STA_WME;
+		rcu_read_unlock();
 		ieee80211_sta_wmm_params(dev, ifsta, elems.wmm_param,
 					 elems.wmm_param_len);
-	}
+	} else
+		rcu_read_unlock();
 
 	/* set AID, ieee80211_set_associated() will tell the driver */
 	bss_conf->aid = aid;
 	ieee80211_set_associated(dev, ifsta, 1);
 
-	rcu_read_unlock();
-
 	ieee80211_associated(dev, ifsta);
 }