dm: usb: Rename usb_find_child to usb_find_emul_child

Now that we unbind usb devices from usb_stop() usb_find_child() is
only necessary to deal with emulated usb devices.

Rename it to make this clear and add a #ifdef to make it a nop in
other cases.

Note the #ifdef turns usb_find_emul_child() into a nop, rather then not
building it and adding another #ifdef to the caller, this is done this way
because adding a #ifdef to the caller is somewhat hairy.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Simon Glass <sjg@chromium.org>

drivers/usb/host/usb-uclass.c

@@ -485,15 +485,14 @@ error:
 }
 
 /**
- * usb_find_child() - Find an existing device which matches our needs
- *
- *
+ * usb_find_emul_child() - Find an existing device for emulated devices
  */
-static int usb_find_child(struct udevice *parent,
-			  struct usb_device_descriptor *desc,
-			  struct usb_interface_descriptor *iface,
-			  struct udevice **devp)
+static int usb_find_emul_child(struct udevice *parent,
+			       struct usb_device_descriptor *desc,
+			       struct usb_interface_descriptor *iface,
+			       struct udevice **devp)
 {
+#ifdef CONFIG_SANDBOX
 	struct udevice *dev;
 
 	*devp = NULL;
@@ -512,7 +511,7 @@ static int usb_find_child(struct udevice *parent,
 			return 0;
 		}
 	}
-
+#endif
 	return -ENOENT;
 }
 
@@ -572,8 +571,8 @@ int usb_scan_device(struct udevice *parent, int port,
 	debug("read_descriptor for '%s': ret=%d\n", parent->name, ret);
 	if (ret)
 		return ret;
-	ret = usb_find_child(parent, &udev->descriptor, iface, &dev);
-	debug("** usb_find_child returns %d\n", ret);
+	ret = usb_find_emul_child(parent, &udev->descriptor, iface, &dev);
+	debug("** usb_find_emul_child returns %d\n", ret);
 	if (ret) {
 		if (ret != -ENOENT)
 			return ret;