netfilter: nf_tables: allow up to 64 bytes in the set element data area

[ fdb9c405e35bdc6e305b9b4e20ebc141ed14fc81 ]

So far, the set elements could store up to 128-bits in the data area.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>