netfilter: nf_tables: fix register ordering

We must register nfnetlink ops last, as that exposes nf_tables to
userspace.  Without this, we could theoretically get nfnetlink request
before net->nft state has been initialized.

Fixes: 99633ab29b ("netfilter: nf_tables: complete net namespace support")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

include/net/netfilter/nf_tables.h

@@ -1374,6 +1374,6 @@ struct nft_trans_flowtable {
 	(((struct nft_trans_flowtable *)trans->data)->flowtable)
 
 int __init nft_chain_filter_init(void);
-void __exit nft_chain_filter_fini(void);
+void nft_chain_filter_fini(void);
 
 #endif /* _NET_NF_TABLES_H */