net/mlx5: prepare sub-policy for flow with meter

net/mlx5: prepare sub-policy for flow with meter

When a flow has a RSS action, the driver splits
each sub flow finally is configured with
a different HW TIR action.

Any RSS action configured in meter policy may cause
a split in the flow configuration.
To save performance, any TIR action will be configured
in different flow table, so policy can be split to
sub-policies per TIR in the flow creation time.

Create a function to prepare the policy and
its sub-policies for a configured flow with meter.

Signed-off-by: Li Zhang <lizh@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>