This adds a very basic test for checking that we present devices
in a way that Linux can consume: boot with both virtio-net-ccw and
virtio-net-pci attached and then verify that Linux is able to see
and detect these devices.

Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Message-Id: <20201126130158.1471985-1-cohuck@redhat.com>