netfilter: nf_tables: add rescheduling points during loop detection walks

[ Upstream commit 81ea0106 ]

Add explicit rescheduling points during ruleset walk.

Switching to a faster algorithm is possible but this is a much
smaller change, suitable for nf tree.

Link: https://bugzilla.netfilter.org/show_bug.cgi?id=1460


Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>