ath9k: fix tx locking issues

The commit "ath9k: simplify tx locking" introduced a soft lockup triggered
by mac80211 sending a BAR frame triggered by a driver call to
ieee80211_tx_send_bar or ieee80211_tx_status.
Fix these issues by queueing processed tx status skbs and submitting them
to mac80211 outside of the lock.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index 130e5db..95276e9 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -196,6 +196,7 @@
 	u8 txq_headidx;
 	u8 txq_tailidx;
 	int pending_frames;
+	struct sk_buff_head complete_q;
 };
 
 struct ath_atx_ac {