Fix build in Kernel 4.11.9

This PR is based on https://github.com/Grawp/rtl8812au_rtl8821au/pull/46/commits/58fc45a4511b8b9d6b52813168e3eee657517b1f to resolve #113

os_dep/linux/ioctl_cfg80211.c

@@ -3336,7 +3336,12 @@ static int rtw_cfg80211_add_monitor_if(_adapter *padapter, char *name, struct ne
 	mon_ndev->type = ARPHRD_IEEE80211_RADIOTAP;
 	strncpy(mon_ndev->name, name, IFNAMSIZ);
 	mon_ndev->name[IFNAMSIZ - 1] = 0;
-	mon_ndev->destructor = rtw_ndev_destructor;
+#if (LINUX_VERSION_CODE>=KERNEL_VERSION(4,11,9))
+	mon_ndev->needs_free_netdev = false;
+	mon_ndev->priv_destructor = rtw_ndev_destructor;
+#else
+  	mon_ndev->destructor = rtw_ndev_destructor;
+#endif
 	
 #if (LINUX_VERSION_CODE>=KERNEL_VERSION(2,6,29))
 	mon_ndev->netdev_ops = &rtw_cfg80211_monitor_if_ops;