net/mlx4: revert workaround for broken Verbs

net/mlx4: revert workaround for broken Verbs

This workaround was needed to properly handle device removal with old
Mellanox OFED releases that are not supported by this PMD anymore.

Starting from rdma-core v16 this removal issue shouldn't happen when
setting MLX4_DEVICE_FATAL_CLEANUP environment variable to 1.

Set the aforementioned variable to 1.

Reverts: 5f4677c6ad5e ("net/mlx4: workaround verbs error after plug-out")
Cc: stable@dpdk.org
Signed-off-by: Matan Azrad <matan@mellanox.com>
Acked-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>