netfilter: nf_tables: attach net_device to basechain

The device is part of the hook configuration, so instead of a global
configuration per table, set it to each of the basechain that we create.

This patch reworks ebddf1a8 ("netfilter: nf_tables: allow to bind table to
net_device").

Note that this adds a dev_name field in the nft_base_chain structure which is
required the netdev notification subscription that follows up in a patch to
handle gone net_devices.

Suggested-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>