mac80211: Fix handling of retry count of NO_ACK frames in minstrel

Make the retry count zero (total try count = 1) for frames with
IEEE80211_TX_CTL_NO_ACK set.

Also remove the check for is_multicast_ether_addr in use_low_rate,
which is redundant because all multicasts have IEEE80211_TX_CTL_NO_ACK
set.
Signed-off-by: NGábor Stefanik <netrolller.3d@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

net/mac80211/rc80211_minstrel.c

@@ -80,8 +80,7 @@ use_low_rate(struct sk_buff *skb)
 	fc = le16_to_cpu(hdr->frame_control);
 
 	return ((info->flags & IEEE80211_TX_CTL_NO_ACK) ||
-		(fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA ||
-		is_multicast_ether_addr(hdr->addr1));
+		(fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA);
 }
 
 
@@ -245,7 +244,10 @@ minstrel_get_rate(void *priv, struct ieee80211_sta *sta,
 
 	if (!sta || !mi || use_low_rate(skb)) {
 		ar[0].idx = rate_lowest_index(sband, sta);
-		ar[0].count = mp->max_retry;
+		if (info->flags & IEEE80211_TX_CTL_NO_ACK)
+			ar[0].count = 1;
+		else
+			ar[0].count = mp->max_retry;
 		return;
 	}