crypto/mlx5: add maximum segments configuration

crypto/mlx5: add maximum segments configuration

The mlx5 HW crypto operations are done by attaching crypto property
to a memory region. Once done, every access to the memory via the
crypto-enabled memory region will result with in-line encryption or
decryption of the data.

As a result, the design choice is to provide two types of WQEs. One
is UMR WQE which sets the crypto property and the other is rdma write
WQE which sends DMA command to copy data from local MR to remote MR.

The size of the WQEs will be defined by a new devarg called
max_segs_num.

This devarg also defines the maximum segments in mbuf chain that will be
supported for crypto operations.

Signed-off-by: Suanming Mou <suanmingm@nvidia.com>
Signed-off-by: Matan Azrad <matan@nvidia.com>
Acked-by: Akhil Goyal <gakhil@marvell.com>