mac802154: Fixes kernel oops when unloading a radio driver

Destroying the workqueue before unregistering the net device caused a
kernel oops

Signed-off-by: Koen Zandberg <[e-mail]>
Acked-by: Alexander Aring <[e-mail]>
Signed-off-by: Marcel Holtmann <[e-mail]>

net/mac802154/main.c

···
 
 	tasklet_kill(&local->tasklet);
 	flush_workqueue(local->workqueue);
-	destroy_workqueue(local->workqueue);
 
 	rtnl_lock();
 
···
 
 	rtnl_unlock();
 
+	destroy_workqueue(local->workqueue);
 	wpan_phy_unregister(local->phy);
 }
 EXPORT_SYMBOL(ieee802154_unregister_hw);