net/mlx5: fix meter policy creation assert

net/mlx5: fix meter policy creation assert

The meter policy creation doesn't belong to flow rule creation
process, so thread workspace was not initialized and there will be
assert error when using it.

This patch removes the incorrect using of thread workspace in meter
policy creation, and adds a flag in policy instead. When creating
flow rule, can use the flag to set the mark flag in thread workspace.

Fixes: 082becbf1f35 ("net/mlx5: fix mark enabling for Rx")
Cc: stable@dpdk.org
Signed-off-by: Shun Hao <shunh@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>