bonding: always set recv_probe to bond_arp_rcv in arp monitor

Currently we only set bond_arp_rcv() if we're using arp_validate, however
this makes us skip updating last_arp_rx if we're not validating incoming
ARPs - thus, if arp_validate is off, last_arp_rx will never be updated.

Fix this by always setting up recv_probe = bond_arp_rcv, even if we're not
using arp_validate.

CC: Jay Vosburgh <fubar@us.ibm.com>
CC: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -3059,7 +3059,6 @@ static int bond_open(struct net_device *bond_dev)
 
 	if (bond->params.arp_interval) {  /* arp interval, in milliseconds. */
 		queue_delayed_work(bond->wq, &bond->arp_work, 0);
-		if (bond->params.arp_validate)
 		bond->recv_probe = bond_arp_rcv;
 	}
 

drivers/net/bonding/bond_options.c

@@ -810,7 +810,6 @@ int bond_option_arp_interval_set(struct bonding *bond,
 			cancel_delayed_work_sync(&bond->arp_work);
 		} else {
 			/* arp_validate can be set only in active-backup mode */
-			if (bond->params.arp_validate)
 			bond->recv_probe = bond_arp_rcv;
 			cancel_delayed_work_sync(&bond->mii_work);
 			queue_delayed_work(bond->wq, &bond->arp_work, 0);