netfilter: nfnetlink_queue: enable UID/GID socket info retrieval

netfilter: nfnetlink_queue: enable UID/GID socket info retrieval

Thanks to commits b304b48 (ipv4: Early TCP socket demux) and f6730a0
(udp: ipv4: Add udp early demux) it is now possible to parse UID and
GID socket info also for incoming TCP and UDP connections. Having
this info available, it is convenient to let NFQUEUE parse it in
order to improve and refine the traffic analysis in userspace.

Signed-off-by: Valentina Giusti <valentina.giusti@bmw-carit.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>