tc: adjust xtables_match and xtables_target to changes in recent iptables

tc: adjust xtables_match and xtables_target to changes in recent iptables

iptables commit 933400b37d09 ("nft: xtables: add the infrastructure to translate from iptables to nft")
added an additional member to struct xtables_match and struct xtables_target.

This change is available for libxtables12 and up.
Add these members conditionally to support both newer and older versions.

Fixes: dd29621578d2 ("tc: add em_ipt ematch for calling xtables matches from tc matching context")
Signed-off-by: Eyal Birger <eyal.birger@gmail.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>