netfilter: flowtable: Remove redundant hw refresh bit

Offloading conns could fail for multiple reasons and a hw refresh bit is
set to try to reoffload it in next sw packet.
But it could be in some cases and future points that the hw refresh bit
is not set but a refresh could succeed.
Remove the hw refresh bit and do offload refresh if requested.
There won't be a new work entry if a work is already pending
anyway as there is the hw pending bit.

Fixes: 8b3646d6

 ("net/sched: act_ct: Support refreshing the flow table entries")
Signed-off-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>