net/mlx5: Accel, Add IPSec acceleration interface

Add routines for manipulating the hardware IPSec SA database (SADB).

In Innova IPSec, a Security Association (SA) is added or deleted
via a command message over the SBU connection.
The HW then sends a response message over the same connection.

Add implementation for Innova IPSec (FPGA-based) hardware.

These routines will be used by the IPSec offload support in a later patch
However they may also be used by others such as RDMA and RoCE IPSec.

mlx5/accel is a middle acceleration layer to allow mlx5e and other ULPs
to work directly with mlx5_core rather than Innova FPGA or other mlx5
acceleration providers.

In this patchset we add Innova IPSec support and mlx5/accel delegates
IPSec offloads to Innova routines.

In the future, when IPSec/TLS or any other acceleration gets integrated
into ConnectX chip, mlx5/accel layer will provide the integrated
acceleration, rather than the Innova one.

Signed-off-by: Ilan Tayari <ilant@mellanox.com>
Signed-off-by: Boris Pismenny <borisp@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>