netfilter: nf_tables: fix netdev hook allocation memleak with dormant tables

netfilter: nf_tables: fix netdev hook allocation memleak with dormant tables

sashiko says:
 could the related code in __nf_tables_abort() leak the struct nft_hook objects when the table is dormant?

 In __nf_tables_abort(), when rolling back a NEWCHAIN transaction that
 updates hooks, the code conditionally unregisters and frees the hooks only
 if the table is not dormant [..]
            if (!(table->flags & NFT_TABLE_F_DORMANT)) {
                nft_netdev_unregister_hooks(net,
                                            &nft_trans_chain_hooks(trans),
                                            true);
            }
            ...
            nft_trans_destroy(trans);

Unfortunately netdev family mixes hook registration and allocation.
Push table struct down and only check for the flag to unregister.

Fixes: 216e7bf7402c ("netfilter: nf_tables: skip netdev hook unregistration if table is dormant")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>