pppoe: drop PPPOX_ZOMBIEs in pppoe_flush_dev

otherwise we loop forever if a PPPoE socket was set
to PPPOX_ZOMBIE state by a PADT message when the
ethernet device is going down afterwards.
Signed-off-by: NUlrich Weber <uweber@astaro.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/pppoe.c

@@ -317,7 +317,7 @@ static void pppoe_flush_dev(struct net_device *dev)
 			lock_sock(sk);
 
 			if (po->pppoe_dev == dev &&
-			    sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND)) {
+			    sk->sk_state & (PPPOX_CONNECTED | PPPOX_BOUND | PPPOX_ZOMBIE)) {
 				pppox_unbind_sock(sk);
 				sk->sk_state = PPPOX_ZOMBIE;
 				sk->sk_state_change(sk);