mac80211: avoid useless memory write on each frame RX

In the likely case that probe_count is 0, don't write to the
memory there.

Also use ifmgd consistently in the function, instead of using
sdata->u.mgd as well.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/mlme.c

@@ -122,15 +122,16 @@ void ieee80211_sta_reset_conn_monitor(struct ieee80211_sub_if_data *sdata)
 {
 	struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
 
-	if (unlikely(!sdata->u.mgd.associated))
+	if (unlikely(!ifmgd->associated))
 		return;
 
-	ifmgd->probe_send_count = 0;
+	if (ifmgd->probe_send_count)
+		ifmgd->probe_send_count = 0;
 
 	if (ieee80211_hw_check(&sdata->local->hw, CONNECTION_MONITOR))
 		return;
 
-	mod_timer(&sdata->u.mgd.conn_mon_timer,
+	mod_timer(&ifmgd->conn_mon_timer,
 		  round_jiffies_up(jiffies + IEEE80211_CONNECTION_IDLE_TIME));
 }