vhost-test: remove meaningless debug info

remove printk as it is meaningless.

Signed-off-by: Liming Wu <liming.wu@jaguarmicro.com>
Message-Id: <20230105070357.274-1-liming.wu@jaguarmicro.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>