[NETFILTER]: add correct bridging support to nfnetlink_{queue,log}

This patch adds support for passing the real 'physical' device ifindex
down to userspace via nfnetlink_log and nfnetlink_queue.

This feature basically obsoletes net/bridge/netfilter/ebt_ulog.c, and
it is likely ebt_ulog.c will die with one of the next couple of
patches.

Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>