This patch adds entry for the vhost-user-rng related files.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Message-Id: <20210614202842.581640-6-mathieu.poirier@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>