ipset: add backport patch for IPv6 nftables ipset-translation

ipset: add backport patch for IPv6 nftables ipset-translation

When porting mwan3 from iptables to nftables I tried the new translation
tool for ipset ipset-translate. I noticed that no IPv6 ipset can be
created with the tool. I have reported the problem to the upstream
project and the following patch fixes the problem.

Until this upsream is included in a new release, this patch should be
used in Openwrt.

https://lore.kernel.org/netfilter-devel/20220228190217.2256371-1-pablo@netfilter.org/T/#m09cc3cb738f2e42024c7aecf5b7240d9f6bbc19c

Signed-off-by: Florian Eckert <fe@dev.tdt.de>