net/sched: act_ct: Support refreshing the flow table entries

If driver deleted an FT entry, a FT failed to offload, or registered to the
flow table after flows were already added, we still get packets in
software.

For those packets, while restoring the ct state from the flow table
entry, refresh it's hardware offload.

Signed-off-by: Paul Blakey <paulb@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>