carl9170: improve unicast PS buffering

Using the ieee80211_sta_block allows the PS code
to handle awake->doze->awake transitions of our
clients in a race-free manner.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/carl9170/carl9170.h b/drivers/net/wireless/ath/carl9170/carl9170.h
index 9cad061..beb725d 100644
--- a/drivers/net/wireless/ath/carl9170/carl9170.h
+++ b/drivers/net/wireless/ath/carl9170/carl9170.h
@@ -448,6 +448,8 @@
 
 struct carl9170_sta_info {
 	bool ht_sta;
+	bool sleeping;
+	atomic_t pending_frames;
 	unsigned int ampdu_max_len;
 	struct carl9170_sta_tid *agg[CARL9170_NUM_TID];
 	struct carl9170_ba_stats stats[CARL9170_NUM_TID];