netfilter: flowtable: fix excessive hw offload attempts after failure

netfilter: flowtable: fix excessive hw offload attempts after failure

[ Upstream commit 396ef64113a8ba01c46315d67a99db8dde3eef51 ]

If a flow cannot be offloaded, the code currently repeatedly tries again as
quickly as possible, which can significantly increase system load.
Fix this by limiting flow timeout update and hardware offload retry to once
per second.

Fixes: c07531c01d82 ("netfilter: flowtable: Remove redundant hw refresh bit")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>