net/mlx5e: TC, Remove special handling of CT action

CT action has special treating as a per-flow action since
it was assumed to be singular and reordered to be first on
the action list.

This isn't the case anymore, and can be converted to just a
FWD to pre_ct + MODIFY_HEAD, and handled per post_act rule.

Remove special handling of CT action, and offload it while
post parsing each ct attribute.

Signed-off-by: Paul Blakey <paulb@nvidia.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>