compress/mlx5: introduce PMD

compress/mlx5: introduce PMD

Add a new compress PMD for Mellanox devices.

The MLX5 compress driver library provides support for Mellanox
BlueField 2 families of 25/50/100/200 Gb/s adapters.

GGAs (Generic Global Accelerators) are offload engines that can be used
to do memory to memory tasks on data.
These engines are part of the ARM complex of the BlueField 2 chip, and
as such they do not use NIC related resources (e.g. RX/TX bandwidth).
They do share the same PCI and memory bandwidth.

So, using the BlueField 2 device, the compress class operations can be
run in parallel to the net, vdpa, and regex class operations.

This driver is depending on rdma-core like the other mlx5 PMDs, also it
is going to use mlx5 DevX to create HW objects directly by the FW.

Add the probing functions, PCI bus connectivity, HW capabilities checks
and some basic objects preparations.

Signed-off-by: Matan Azrad <matan@nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>