iavf: use unregister_netdev

Use unregister_netdev, which takes rtnl_lock for us. We don't have to
check the reg_state under rtnl_lock. There's nothing to race with. We
have just cancelled the finish_config work.
Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://lore.kernel.org/r/20231027175941.1340255-7-jacob.e.keller@intel.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/intel/iavf/iavf_main.c

@@ -5167,10 +5167,8 @@ static void iavf_remove(struct pci_dev *pdev)
 	cancel_delayed_work_sync(&adapter->watchdog_task);
 	cancel_work_sync(&adapter->finish_config);
 
-	rtnl_lock();
 	if (netdev->reg_state == NETREG_REGISTERED)
-		unregister_netdevice(netdev);
-	rtnl_unlock();
+		unregister_netdev(netdev);
 
 	if (CLIENT_ALLOWED(adapter)) {
 		err = iavf_lan_del_device(adapter);