mac80211: probe the AP when resuming

Check the connection by probing the AP (either using nullfunc or a
probe request). If nullfunc probing is supported and the assoc is no
longer valid, the AP will send a disassoc/deauth immediately.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/mlme.c

@@ -2021,6 +2021,7 @@ void ieee80211_sta_restart(struct ieee80211_sub_if_data *sdata)
 	if (test_and_clear_bit(TMR_RUNNING_CHANSW, &ifmgd->timers_running))
 		add_timer(&ifmgd->chswitch_timer);
 	ieee80211_sta_reset_beacon_monitor(sdata);
+	ieee80211_restart_sta_timer(sdata);
 }
 #endif