rc80211-pid: fix sta_info refcounting

Fix a bug which caused uncorrect refcounting of PHYs in mac80211. Thanks to
Johannes Berg for spotting this out.

Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: NStefano Brivio <stefano.brivio@polimi.it>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/mac80211/rc80211_pid_algo.c

@@ -254,7 +254,7 @@ static void rate_control_pid_tx_status(void *priv, struct net_device *dev,
 	/* Ignore all frames that were sent with a different rate than the rate
 	 * we currently advise mac80211 to use. */
 	if (status->control.rate != &local->oper_hw_mode->rates[sta->txrate])
-		return;
+		goto ignore;
 
 	spinfo = sta->rate_ctrl_priv;
 	spinfo->tx_num_xmit++;
@@ -295,6 +295,7 @@ static void rate_control_pid_tx_status(void *priv, struct net_device *dev,
 	if (time_after(jiffies, spinfo->last_sample + period))
 		rate_control_pid_sample(pinfo, local, sta);
 
+ignore:
 	sta_info_put(sta);
 }