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 If nullfunc probing is supported and the assoc is no
longer valid, the AP will send a disassoc/deauth immediately.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>
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 729aba4..849d9c6 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -2021,6 +2021,7 @@
 	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