bonding: use last_arp_rx in slave_last_rx()

Now that last_arp_rx really has the last time we've received any (validated or
not) ARP, we can use it in slave_last_rx() instead of slave->dev->last_rx.

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/bonding.h

@@ -379,14 +379,10 @@ static inline unsigned long slave_oldest_target_arp_rx(struct bonding *bond,
 static inline unsigned long slave_last_rx(struct bonding *bond,
 					struct slave *slave)
 {
-	if (slave_do_arp_validate(bond, slave)) {
 	if (bond->params.arp_all_targets == BOND_ARP_TARGETS_ALL)
 		return slave_oldest_target_arp_rx(bond, slave);
-		else
-			return slave->last_arp_rx;
-	}
 
-	return slave->dev->last_rx;
+	return slave->last_arp_rx;
 }
 
 #ifdef CONFIG_NET_POLL_CONTROLLER