bridge: netlink: add support for netfilter tables config

Add support to allow getting/setting netfilter tables settings.
Currently these are IFLA_BR_NF_CALL_IPTABLES, IFLA_BR_NF_CALL_IP6TABLES
and IFLA_BR_NF_CALL_ARPTABLES.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>