mac80211: move beacon_loss_count into ifmgd

There's little point in keeping (and even sending to userspace)
the beacon_loss_count value per station, since it can only apply
to the AP on a managed-mode connection. Move the value to ifmgd,
advertise it only in managed mode, and remove it from ethtool as
it's available through better interfaces.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/ethtool.c b/net/mac80211/ethtool.c
index 188faab..3fbf9c3 100644
--- a/net/mac80211/ethtool.c
+++ b/net/mac80211/ethtool.c
@@ -40,7 +40,7 @@
 	"rx_duplicates", "rx_fragments", "rx_dropped",
 	"tx_packets", "tx_bytes",
 	"tx_filtered", "tx_retry_failed", "tx_retries",
-	"beacon_loss", "sta_state", "txrate", "rxrate", "signal",
+	"sta_state", "txrate", "rxrate", "signal",
 	"channel", "noise", "ch_time", "ch_time_busy",
 	"ch_time_ext_busy", "ch_time_rx", "ch_time_tx"
 };
@@ -90,7 +90,6 @@
 		data[i++] += sta->tx_filtered_count;	\
 		data[i++] += sta->tx_retry_failed;	\
 		data[i++] += sta->tx_retry_count;	\
-		data[i++] += sta->beacon_loss_count;	\
 	} while (0)
 
 	/* For Managed stations, find the single station based on BSSID