net/mlx5: support meter action in meter policy

net/mlx5: support meter action in meter policy

This makes the meter policy support meter action. So multiple meters
can be chained as a meter hierarchy.

Only termination meter is allowed as the last meter in a hierarchy,
and there're two cases:
1. The last meter has non-RSS policy, can directly create sub-policy
and color rules during each meter's policy creation.
2. The last meter has RSS policy, don't create sub-policy/rules when
creating meter policy. Only when a RTE flow is using the meter hierarchy,
will iterate all meters of the hierarchy and create needed sub-
policies and color rules for them.

Signed-off-by: Shun Hao <shunh@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>