netfilter: nf_tables: add missing netlink attrs to policies

Fixes: 8aeff920 ("netfilter: nf_tables: add stateful object reference to set elements")
Fixes: f25ad2e9 ("netfilter: nf_tables: prepare for expressions associated to set elements")
Fixes: 1a94e38d ("netfilter: nf_tables: add NFTA_RULE_ID attribute")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>