pppoe: uninitialized variable in pppoe_flush_dev()

This assignment got deleted along with the checks by mistake.  This
comes from:  8753d29fd "pppoe: remove unnecessary checks in
pppoe_flush_dev"

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/pppoe.c b/drivers/net/pppoe.c
index b1b93ff..805b64d 100644
--- a/drivers/net/pppoe.c
+++ b/drivers/net/pppoe.c
@@ -289,6 +289,7 @@
 	struct pppoe_net *pn;
 	int i;
 
+	pn = pppoe_pernet(dev_net(dev));
 	write_lock_bh(&pn->hash_lock);
 	for (i = 0; i < PPPOE_HASH_SIZE; i++) {
 		struct pppox_sock *po = pn->hash_table[i];