netfilter: nft_dynset: add timeout extension to template

commit 0c5b7a50 upstream.

Otherwise, the newly create element shows no timeout when listing the
ruleset. If the set definition does not specify a default timeout, then
the set element only shows the expiration time, but not the timeout.
This is a problem when restoring a stateful ruleset listing since it
skips the timeout policy entirely.

Fixes: 22fe54d5

 ("netfilter: nf_tables: add support for dynamic set updates")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>