mac80211: remove last_probe_resp from bss

We track this, but never use it, so we can
just remove it.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/ieee80211_i.h

@@ -95,8 +95,6 @@ struct ieee80211_bss {
 	bool wmm_used;
 	bool uapsd_supported;
 
-	unsigned long last_probe_resp;
-
 #ifdef CONFIG_MAC80211_MESH
 	u8 *mesh_id;
 	size_t mesh_id_len;

net/mac80211/scan.c

@@ -146,9 +146,6 @@ ieee80211_bss_info_update(struct ieee80211_local *local,
 			bss->valid_data |= IEEE80211_BSS_VALID_WMM;
 	}
 
-	if (!beacon)
-		bss->last_probe_resp = jiffies;
-
 	return bss;
 }