mac80211: avoid calling useless channel context code

ieee80211_assign_chanctx() checks if local->use_chanctx is true, so
the two code block related to ieee80211_assign_chanctx() can be moved
into above if clause, emphasize that these code are executed only if
local->use_chanctx is true.
Signed-off-by: Zhao, Gang <gamerh2o@gmail.com>
[change subject]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/util.c

@@ -1565,7 +1565,6 @@ int ieee80211_reconfig(struct ieee80211_local *local)
 		list_for_each_entry(ctx, &local->chanctx_list, list)
 			WARN_ON(drv_add_chanctx(local, ctx));
 		mutex_unlock(&local->chanctx_mtx);
-	}
 
 		list_for_each_entry(sdata, &local->interfaces, list) {
 			if (!ieee80211_sdata_running(sdata))
@@ -1576,6 +1575,7 @@ int ieee80211_reconfig(struct ieee80211_local *local)
 		sdata = rtnl_dereference(local->monitor_sdata);
 		if (sdata && ieee80211_sdata_running(sdata))
 			ieee80211_assign_chanctx(local, sdata);
+	}
 
 	/* add STAs back */
 	mutex_lock(&local->sta_mtx);