cfg80211: implement get_wireless_stats

By dropping the noise reporting, we can implement
wireless stats in cfg80211. We also make the
handler return NULL if we have no information,
which is possible thanks to the recent wext change.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 5790855..fe87819 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1646,6 +1646,7 @@
 int cfg80211_wext_giwtxpower(struct net_device *dev,
 			     struct iw_request_info *info,
 			     union iwreq_data *data, char *keybuf);
+struct iw_statistics *cfg80211_wireless_stats(struct net_device *dev);
 
 int cfg80211_wext_siwpower(struct net_device *dev,
 			   struct iw_request_info *info,