mac80211: clear sta.drv_priv on reconfiguration

drivers might assume sta.drv_priv is clear while
the sta is added, so clear it on reconfinguration.

Signed-off-by: Eliad Peller <eliad@wizery.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/util.c

@@ -1205,6 +1205,7 @@ int ieee80211_reconfig(struct ieee80211_local *local)
 					     struct ieee80211_sub_if_data,
 					     u.ap);
 
+			memset(&sta->sta.drv_priv, 0, hw->sta_data_size);
 			WARN_ON(drv_sta_add(local, sdata, &sta->sta));
 		}
 	}