ipv4: remove useless codes in ipmr_device_event()

Commit 7dc00c82 added a 'notify' parameter for vif_delete() to
distinguish whether to unregister the device.

When notify=1 means we does not need to unregister the device,
so calling unregister_netdevice_many is useless.
Signed-off-by: NRongQing.Li <roy.qing.li@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/ipmr.c

@@ -1520,7 +1520,6 @@ static int ipmr_device_event(struct notifier_block *this, unsigned long event, v
 	struct mr_table *mrt;
 	struct vif_device *v;
 	int ct;
-	LIST_HEAD(list);
 
 	if (event != NETDEV_UNREGISTER)
 		return NOTIFY_DONE;
@@ -1529,10 +1528,9 @@ static int ipmr_device_event(struct notifier_block *this, unsigned long event, v
 		v = &mrt->vif_table[0];
 		for (ct = 0; ct < mrt->maxvif; ct++, v++) {
 			if (v->dev == dev)
-				vif_delete(mrt, ct, 1, &list);
+				vif_delete(mrt, ct, 1, NULL);
 		}
 	}
-	unregister_netdevice_many(&list);
 	return NOTIFY_DONE;
 }