bonding: use the new options to correctly set last_arp_rx

Now that the options are in place - arp_validate can be set to receive all
the traffic or only arp packets to verify if the slave is up, when the
slave isn't validated.

CC: Rob Landley <rob@landley.net>
CC: "David S. Miller" <davem@davemloft.net>
CC: Nikolay Aleksandrov <nikolay@redhat.com>
CC: Ding Tianhong <dingtianhong@huawei.com>
CC: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>