ath10k: fix NULL deref upon early FW crash

If firmware crashes during FW probing it would try
to perform FW recovery which uses mac80211
workqueue before registering to mac80211.

Using internal workqueue solves the problem.
Signed-off-by: NMichal Kazior <michal.kazior@tieto.com>
Signed-off-by: NKalle Valo <kvalo@qca.qualcomm.com>

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

@@ -664,7 +664,8 @@ static void ath10k_core_restart(struct work_struct *work)
 		ieee80211_restart_hw(ar->hw);
 		break;
 	case ATH10K_STATE_OFF:
-		/* this can happen if driver is being unloaded */
+		/* this can happen if driver is being unloaded
+		 * or if the crash happens during FW probing */
 		ath10k_warn("cannot restart a device that hasn't been started\n");
 		break;
 	case ATH10K_STATE_RESTARTING:

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

@@ -777,7 +777,7 @@ static void ath10k_pci_hif_dump_area(struct ath10k *ar)
 			   reg_dump_values[i + 2],
 			   reg_dump_values[i + 3]);
 
-	ieee80211_queue_work(ar->hw, &ar->restart_work);
+	queue_work(ar->workqueue, &ar->restart_work);
 }
 
 static void ath10k_pci_hif_send_complete_check(struct ath10k *ar, u8 pipe,