fwctl subsystem

JIRA: https://issues.redhat.com/browse/RHEL-86016

fwctl is a new subsystem intended to bring some common rules and order to
the growing pattern of exposing a secure FW interface directly to
userspace. Unlike existing places like RDMA/DRM/VFIO/uacce that are
exposing a device for datapath operations fwctl is focused on debugging,
configuration and provisioning of the device.

In particular, fwctl is an upstream approach to provide a configuration
interface for low-level tunables for mlx5 devices.

Signed-off-by: Benjamin Poirier bpoirier@redhat.com