uapi: fix linux/netfilter/xt_hashlimit.h userspace compilation error

Include <linux/limits.h> like some of uapi/linux/netfilter/xt_*.h
headers do to fix the following linux/netfilter/xt_hashlimit.h
userspace compilation error:

/usr/include/linux/netfilter/xt_hashlimit.h:90:12: error: 'NAME_MAX' undeclared here (not in a function)
  char name[NAME_MAX];

Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>