[NETFILTER]: nfnetlink_queue: fix nfnetlink message size

Fix oversized message, use NLMSG_SPACE just one since it reserves space
for the netlink header and NFA_SPACE for every attribute.

Thanks to Harald Welte for the feedback

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>