Minor cleanup to return after WNM Action frame handling

There is no need to go through the following handler calls in
hostapd_action_rx() after having found the matching WLAN_ACTION_WNM
handler.

Signed-off-by: Jouni Malinen <j@w1.fi>

src/ap/drv_callbacks.c

@@ -1118,6 +1118,7 @@ static void hostapd_action_rx(struct hostapd_data *hapd,
 #ifdef CONFIG_WNM_AP
 	if (mgmt->u.action.category == WLAN_ACTION_WNM) {
 		ieee802_11_rx_wnm_action_ap(hapd, mgmt, drv_mgmt->frame_len);
+		return;
 	}
 #endif /* CONFIG_WNM_AP */
 #ifdef CONFIG_FST