net/mlx5: fix meter hierarchy validation with yellow

net/mlx5: fix meter hierarchy validation with yellow

In mlx5 PMD, the meter hierarchy only supports the green color. It
means that a meter action can only be in the green action list. In
the meanwhile, the yellow action list should be empty now. Any
action for the yellow color policy will be considered invalid if
the green color policy is a hierarchy.

Also, the error message printing of meter hierarchy validation is
fixed by removing an incorrect checking.

Fixes: 4b7bf3ffb473 ("net/mlx5: support yellow in meter policy validation")
Fixes: a3b7af90baba ("net/mlx5: validate meter action in policy")

Signed-off-by: Bing Zhao <bingz@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>