ipset: Backports for the nla_put_net64() API changes

ipset: Backports for the nla_put_net64() API changes

* Backports the patch "libnl: nla_put_net64():align on a 64-bit area" [1]
  by Nicolas Dichtel <nicolas.dichtel@6wind.com>

* Since the nla_put_net64() API has been changed, therefore, the
  ip_set_compat.h.in should provides the macro IPSET_NLA_PUT_NET64 that
  point to the nla_put_net64() with appropriate number of arguments.

  The build script should distinguish the API changes by detect for
  the existence of nla_put_64bit() function in include/net/netlink.h.
  This function was added in the same patches set and called by
  the nla_put_be64() that called by nla_put_net64() respectively.

[1] https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit?id=e9bbe898cbe89b17ad3993c136aa13d0431cd537

Signed-off-by: Neutron Soutmun <neo.neutron@gmail.com>
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>