bootstd: Correct virtio block-device handling

At present virtio tries to attach QEMU services to a bootdev device, which
cannot work. Add a check for this.

Also use bootdev_setup_sibling_blk() to create the bootdev device, since
it allows the correct name to be used and bootdev_get_sibling_blk() to
work as expected.

The bootdev is not created on sandbox since it does have a real virtio
device and it is not possible to read blocks.

Signed-off-by: Simon Glass <sjg@chromium.org>
Fixes: a60f7a3e35b ("bootstd: Add a virtio bootdev")
Reported-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
diff --git a/drivers/virtio/virtio-uclass.c b/drivers/virtio/virtio-uclass.c
index 91af412..de9bc90 100644
--- a/drivers/virtio/virtio-uclass.c
+++ b/drivers/virtio/virtio-uclass.c
@@ -247,8 +247,8 @@
 	}
 	device_set_name_alloced(vdev);
 
-	if (uc_priv->device == VIRTIO_ID_BLOCK) {
-		ret = bootdev_setup_for_dev(udev, name);
+	if (uc_priv->device == VIRTIO_ID_BLOCK && !IS_ENABLED(CONFIG_SANDBOX)) {
+		ret = bootdev_setup_sibling_blk(vdev, "virtio_bootdev");
 		if (ret)
 			return log_msg_ret("bootdev", ret);
 	}
@@ -275,6 +275,10 @@
 	int i;
 	int ret;
 
+	/* bootdevs are not virtio devices */
+	if (device_get_uclass_id(vdev) == UCLASS_BOOTDEV)
+		return 0;
+
 	/*
 	 * Save the real virtio device (eg: virtio-net, virtio-blk) to
 	 * the transport (parent) device's uclass priv for future use.