netfilter: nf_tables: skip transaction if update object is not implemented

[ Upstream commit 84b1a0c0 ]

Turn update into noop as a follow up for:

  9fedd894 ("netfilter: nf_tables: fix unexpected EOPNOTSUPP error")

instead of adding a transaction object which is simply discarded at a
later stage of the commit protocol.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Stable-dep-of: cddc0427 ("netfilter: nf_tables: must hold rcu read lock while iterating object type list")
Signed-off-by: Sasha Levin <sashal@kernel.org>