ath9k: initialize ath_node linked list

Initialize neighbor linked list used by dynack to compute ACK timeout
as the maximum STA ACK timeout
Signed-off-by: NLorenzo Bianconi <lorenzo.bianconi83@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/main.c

@@ -345,12 +345,16 @@ static void ath_node_attach(struct ath_softc *sc, struct ieee80211_sta *sta,
 	memset(&an->key_idx, 0, sizeof(an->key_idx));
 
 	ath_tx_node_init(sc, an);
+
+	ath_dynack_node_init(sc->sc_ah, an);
 }
 
 static void ath_node_detach(struct ath_softc *sc, struct ieee80211_sta *sta)
 {
 	struct ath_node *an = (struct ath_node *)sta->drv_priv;
 	ath_tx_node_cleanup(sc, an);
+
+	ath_dynack_node_deinit(sc->sc_ah, an);
 }
 
 void ath9k_tasklet(unsigned long data)