pppoe: remove unnecessary checks in pppoe_flush_dev

pernet memory is guaranteed to exist when notifiers are called.
Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/pppoe.c

@@ -290,12 +290,6 @@ static void pppoe_flush_dev(struct net_device *dev)
 	struct pppoe_net *pn;
 	int i;
 
-	BUG_ON(dev == NULL);
-
-	pn = pppoe_pernet(dev_net(dev));
-	if (!pn) /* already freed */
-		return;
-
 	write_lock_bh(&pn->hash_lock);
 	for (i = 0; i < PPPOE_HASH_SIZE; i++) {
 		struct pppox_sock *po = pn->hash_table[i];