iwlwifi: track IBSS manager status

Only the IBSS manager, ie. the station that sent
the IBSS beacon last, should be replying to probe
responses. This requires implementing the mac80211
tx_last_beacon callback, which we can do thanks to
the ucode beacon notification.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-dev.h b/drivers/net/wireless/iwlwifi/iwl-dev.h
index f35bcad..5996355 100644
--- a/drivers/net/wireless/iwlwifi/iwl-dev.h
+++ b/drivers/net/wireless/iwlwifi/iwl-dev.h
@@ -1109,6 +1109,9 @@
 	u32 ucode_beacon_time;
 	int missed_beacon_threshold;
 
+	/* track IBSS manager (last beacon) status */
+	u32 ibss_manager;
+
 	/* storing the jiffies when the plcp error rate is received */
 	unsigned long plcp_jiffies;