This creates the QEMU side of the vhost-user-scmi device which connects to
the remote daemon.  It is based on code of similar vhost-user devices.

Signed-off-by: Milan Zamazal <mzamazal@redhat.com>
Message-Id: <20230628100524.342666-2-mzamazal@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>