ath10k: flush hif buffers before recovery

Transport buffers weren't flushed and processed
before queueing hw recovery request to mac80211.

This could in theory result in an unwanted htt/wmi
rx events being processed while mac80211 recovers
the device and possibly interfere or even crash
the system.
Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

drivers/net/wireless/ath/ath10k/core.c

@@ -665,6 +665,7 @@ static void ath10k_core_restart(struct work_struct *work)
 	switch (ar->state) {
 	case ATH10K_STATE_ON:
 		ar->state = ATH10K_STATE_RESTARTING;
+		ath10k_hif_stop(ar);
 		ath10k_scan_finish(ar);
 		ieee80211_restart_hw(ar->hw);
 		break;