mac80211: remove sta_info.gtk_idx

This struct member is only assigned, never used otherwise;
remove it.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/key.c

@@ -336,7 +336,6 @@ static void ieee80211_key_replace(struct ieee80211_sub_if_data *sdata,
 			ieee80211_check_fast_xmit(sta);
 		} else {
 			rcu_assign_pointer(sta->gtk[idx], new);
-			sta->gtk_idx = idx;
 		}
 	} else {
 		defunikey = old &&

net/mac80211/sta_info.h

@@ -283,7 +283,6 @@ struct ieee80211_fast_tx {
  * @ptk: peer keys negotiated with this station, if any
  * @ptk_idx: last installed peer key index
  * @gtk: group keys negotiated with this station, if any
- * @gtk_idx: last installed group key index
  * @rate_ctrl: rate control algorithm reference
  * @rate_ctrl_lock: spinlock used to protect rate control data
  *	(data inside the algorithm, so serializes calls there)
@@ -381,7 +380,6 @@ struct sta_info {
 	struct ieee80211_sub_if_data *sdata;
 	struct ieee80211_key __rcu *gtk[NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS];
 	struct ieee80211_key __rcu *ptk[NUM_DEFAULT_KEYS];
-	u8 gtk_idx;
 	u8 ptk_idx;
 	struct rate_control_ref *rate_ctrl;
 	void *rate_ctrl_priv;