bonding, net: Move last_rx update into bonding recv logic

	The only user of the net_device->last_rx field is bonding.
This patch adds a conditional update of last_rx to the bonding special
logic in skb_bond_should_drop, causing last_rx to only be updated when
the ARP monitor is running.

	This frees network device drivers from the necessity of
updating last_rx, which can have cache line thrash issues.

Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 56c823c..39575d7 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -4564,6 +4564,8 @@
 	bond_dev->tx_queue_len = 0;
 	bond_dev->flags |= IFF_MASTER|IFF_MULTICAST;
 	bond_dev->priv_flags |= IFF_BONDING;
+	if (bond->params.arp_interval)
+		bond_dev->priv_flags |= IFF_MASTER_ARPMON;
 
 	/* At first, we block adding VLANs. That's the only way to
 	 * prevent problems that occur when adding VLANs over an