netfilter: ipset: Preprocessor directices cleanup

 * Undefine mtype_data_reset_elem before defining.

 * Remove duplicated mtype_gc_init undefine, move
   mtype_gc_init define closer to mtype_gc define.

 * Use htype instead of HTYPE in IPSET_TOKEN(HTYPE, _create)().

 * Remove PF definition from sets: no more used.

Signed-off-by: Sergey Popovich <popovich_sergei@mail.ua>
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>