mac80211: remove sta_info_flush() from interface teardown

All interface types now properly clean up their stations
using some form of sta_info_flush() themselves, so there's
no need to try it again at teardown. Remove the call to
get rid of the extra delay from the synchronize_net() and
rcu_barrier() calls.
Reported-by: NMoshe Benji <moshe.benji@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>

net/mac80211/iface.c

@@ -1041,7 +1041,6 @@ static void ieee80211_set_multicast_list(struct net_device *dev)
  */
 static void ieee80211_teardown_sdata(struct ieee80211_sub_if_data *sdata)
 {
-	int flushed;
 	int i;
 
 	/* free extra data */
@@ -1055,9 +1054,6 @@ static void ieee80211_teardown_sdata(struct ieee80211_sub_if_data *sdata)
 
 	if (ieee80211_vif_is_mesh(&sdata->vif))
 		mesh_rmc_free(sdata);
-
-	flushed = sta_info_flush(sdata);
-	WARN_ON(flushed);
 }
 
 static void ieee80211_uninit(struct net_device *dev)