net/mlx5: fix meter policy validation

net/mlx5: fix meter policy validation

When a user specifies meter policy like "g_actions queue / end
y_actions queue / r_action drop / end", validation logic missed
to set meter policy mode and it took a random value from the stack.

Define ALL policy modes for the mentioned cases.

Fixes: 4b7bf3ffb473 ("net/mlx5: support yellow in meter policy validation")
Cc: stable@dpdk.org
Signed-off-by: Rongwei Liu <rongweil@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>
Reviewed-by: Bing Zhao <bingz@nvidia.com>