tests: rename virtio_seg_max_adjust to virtio_check_params

Since, virtio_seg_max_adjust checks not only seg_max, but also
virtqueue_size parameter, let's make the test more general and
add new parameters to be checked there in the future.
Signed-off-by: NDenis Plotnikov <dplotnikov@virtuozzo.com>
Message-Id: <20200129140702.5411-5-dplotnikov@virtuozzo.com>
Acked-by: NCornelia Huck <cohuck@redhat.com>
Signed-off-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>