ath9k: dynack: use authentication messages for 'late' ack

In order to properly support dynack in ad-hoc mode running
wpa_supplicant, take into account authentication frames for
'late ack' detection. This patch has been tested on devices
mounted on offshore high-voltage stations connected through
~24Km link
Reported-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
Tested-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

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

@@ -187,7 +187,8 @@ void ath_dynack_sample_tx_ts(struct ath_hw *ah, struct sk_buff *skb,
 	/* late ACK */
 	if (ts->ts_status & ATH9K_TXERR_XRETRY) {
 		if (ieee80211_is_assoc_req(hdr->frame_control) ||
-		    ieee80211_is_assoc_resp(hdr->frame_control)) {
+		    ieee80211_is_assoc_resp(hdr->frame_control) ||
+		    ieee80211_is_auth(hdr->frame_control)) {
 			ath_dbg(common, DYNACK, "late ack\n");
 			ath9k_hw_setslottime(ah, (LATEACK_TO - 3) / 2);
 			ath9k_hw_set_ack_timeout(ah, LATEACK_TO);