netfilter: nf_tables: disallow updates of anonymous sets

[ Upstream commit b770283c ]

Disallow updates of set timeout and garbage collection parameters for
anonymous sets.

Fixes: 123b9961 ("netfilter: nf_tables: honor set timeout and garbage collection updates")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>