net: Fix build regression in rtl8723bs staging driver.

drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c: In function ‘rtw_cfg80211_add_monitor_if’:
drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c:2670:10: error: ‘struct net_device’ has no member named ‘destructor’
  mon_ndev->destructor = rtw_ndev_destructor;
          ^
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c

@@ -2667,7 +2667,8 @@ static int rtw_cfg80211_add_monitor_if (struct adapter *padapter, char *name, st
 	mon_ndev->type = ARPHRD_IEEE80211_RADIOTAP;
 	strncpy(mon_ndev->name, name, IFNAMSIZ);
 	mon_ndev->name[IFNAMSIZ - 1] = 0;
-	mon_ndev->destructor = rtw_ndev_destructor;
+	mon_ndev->needs_free_netdev = true;
+	mon_ndev->priv_destructor = rtw_ndev_destructor;
 
 	mon_ndev->netdev_ops = &rtw_cfg80211_monitor_if_ops;
 

drivers/staging/rtl8723bs/os_dep/os_intfs.c

@@ -1207,8 +1207,6 @@ void rtw_ndev_destructor(struct net_device *ndev)
 
 	if (ndev->ieee80211_ptr)
 		kfree((u8 *)ndev->ieee80211_ptr);
-
-	free_netdev(ndev);
 }
 
 void rtw_dev_unload(struct adapter *padapter)