mac80211: fix IEEE80211_SDATA_DISCONNECT_RESUME

Since commit 12e7f517029dad819c45eca9ca01fdb9ba57616b,
IEEE80211_SDATA_DISCONNECT_RESUME no longer worked as
it would simply never be tested. Restore a bit of the
code removed there and in 9b7d72c1041ec5b20b24af487a9
to make it work again.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 3f87fa4..27e0715 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -1740,6 +1740,13 @@
 	mb();
 	local->resuming = false;
 
+	list_for_each_entry(sdata, &local->interfaces, list) {
+		if (!ieee80211_sdata_running(sdata))
+			continue;
+		if (sdata->vif.type == NL80211_IFTYPE_STATION)
+			ieee80211_sta_restart(sdata);
+	}
+
 	mod_timer(&local->sta_cleanup, jiffies + 1);
 #else
 	WARN_ON(1);