musb: Update usb-compat to work with struct usb_device without a parent ptr

When building with CONFIG_DM_USB=y struct usb_device does not have a parent
pointer. This commit adds support to the musb code to deal with this.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/usb/musb-new/musb_uboot.c b/drivers/usb/musb-new/musb_uboot.c
index 70e87c9..a96e8d2 100644
--- a/drivers/usb/musb-new/musb_uboot.c
+++ b/drivers/usb/musb-new/musb_uboot.c
@@ -97,7 +97,7 @@
 		      buffer, len, setup, 0);
 
 	/* Fix speed for non hub-attached devices */
-	if (!dev->parent)
+	if (!usb_dev_get_parent(dev))
 		dev->speed = host_speed;
 
 	return submit_urb(&hcd, &urb);