bridge: implement rtnl_link_ops->get_size and rtnl_link_ops->fill_info

Allow rtnetlink users to get bridge master info in IFLA_INFO_DATA attr
This initial part implements forward_delay, hello_time, max_age options.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc include/uapi/linux/if_link.h
Simple merge

diff --cc net/bridge/br_netlink.c
Simple merge