netfilter: nf_tables_bridge: set the pktinfo for IPv4/IPv6 traffic

This patch adds the missing bits to allow to match per meta l4proto from
the bridge. Example:

  nft add rule bridge filter input ether type {ip, ip6} meta l4proto udp counter

Signed-off-by: Alvaro Neira Ayuso <alvaroneay@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>