mac80211_hwsim: Set IEEE80211_STAT_ACK flag when userspace indicates that the frame has been acknowledged.

The station fail average is not updated correctly since the
IEEE80211_STAT_ACK flag is not set when using wmediumd with
mac80211_hwsim. Set this flag when wmediumd indicates that the frame
was successfully transmitted (eventually).

Signed-off-by: Qasim Javed <qasimj@gmail.com>
Signed-off-by: Javier Cardona <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/mac80211_hwsim.c

@@ -1555,6 +1555,7 @@ static int hwsim_tx_info_frame_received_nl(struct sk_buff *skb_2,
 			hdr = (struct ieee80211_hdr *) skb->data;
 			mac80211_hwsim_monitor_ack(data2->hw, hdr->addr2);
 		}
+		txi->flags |= IEEE80211_TX_STAT_ACK;
 	}
 	ieee80211_tx_status_irqsafe(data2->hw, skb);
 	return 0;