ath10k: improve beacon submission latency

The patch prevents beacon misses in some case of
heavy load on a system.

If a beacon can't be transmitted directly from an
SWBA event it will be left in arvif->beacon and
transmission will be retried once TX credits
become available.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
diff --git a/drivers/net/wireless/ath/ath10k/core.h b/drivers/net/wireless/ath/ath10k/core.h
index c953a33..14b7d3d 100644
--- a/drivers/net/wireless/ath/ath10k/core.h
+++ b/drivers/net/wireless/ath/ath10k/core.h
@@ -204,6 +204,7 @@
 	enum wmi_vdev_subtype vdev_subtype;
 	u32 beacon_interval;
 	u32 dtim_period;
+	struct sk_buff *beacon;
 
 	struct ath10k *ar;
 	struct ieee80211_vif *vif;