bonding: add slave_changelink support and use it for queue_id

bonding: add slave_changelink support and use it for queue_id

This patch adds support for slave_changelink to the bonding and uses it
to give the ability to change the queue_id of the enslaved devices via
netlink. It sets slave_maxtype and uses bond_changelink as a prototype for
bond_slave_changelink.
Example/test command after the iproute2 patch:
 ip link set eth0 type bond_slave queue_id 10

CC: David S. Miller <davem@davemloft.net>
CC: Jay Vosburgh <j.vosburgh@gmail.com>
CC: Veaceslav Falico <vfalico@gmail.com>
CC: Andy Gospodarek <andy@greyhouse.net>
Suggested-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Acked-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>