ath10k: cancel coverage class work during stop and restart

It seems set_coverage_class_work is not cancelled anywhere,
though I could not find a crash/warning  with this existing
design, its safer to cancel it during stop() and also before
restarting the hardware.
Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qti.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

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

@@ -1627,6 +1627,13 @@ static void ath10k_core_restart(struct work_struct *work)
 	wake_up(&ar->wmi.tx_credits_wq);
 	wake_up(&ar->peer_mapping_wq);
 
+	/* TODO: We can have one instance of cancelling coverage_class_work by
+	 * moving it to ath10k_halt(), so that both stop() and restart() would
+	 * call that but it takes conf_mutex() and if we call cancel_work_sync()
+	 * with conf_mutex it will deadlock.
+	 */
+	cancel_work_sync(&ar->set_coverage_class_work);
+
 	mutex_lock(&ar->conf_mutex);
 
 	switch (ar->state) {

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

@@ -4717,6 +4717,7 @@ static void ath10k_stop(struct ieee80211_hw *hw)
 	}
 	mutex_unlock(&ar->conf_mutex);
 
+	cancel_work_sync(&ar->set_coverage_class_work);
 	cancel_delayed_work_sync(&ar->scan.timeout);
 	cancel_work_sync(&ar->restart_work);
 }