nfp: flower: refactor action offload code slightly

Change the action related offload functions to take in flow_rule *
as input instead of flow_cls_offload * as input. The flow_rule
parts of flow_cls_offload is the only part that is used in any
case, and this is required for more conntrack offload patches
which will follow later.

Signed-off-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Yinjun Zhang <yinjun.zhang@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>