usb: gadget: sandbox: Drop dm_usb_gadget_handle_interrupts()

Drop dm_usb_gadget_handle_interrupts() in favor of empty default
implementation of the same in drivers/usb/gadget/udc/udc-uclass.c .

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Tested-by: Mattijs Korpershoek <mkorpershoek@baylibre.com> # vim3
Link: https://lore.kernel.org/r/20240614005309.34433-11-marek.vasut+renesas@mailbox.org
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
diff --git a/drivers/usb/host/usb-sandbox.c b/drivers/usb/host/usb-sandbox.c
index e26f0b2..f687fe2 100644
--- a/drivers/usb/host/usb-sandbox.c
+++ b/drivers/usb/host/usb-sandbox.c
@@ -123,12 +123,7 @@
 	return ret;
 }
 
-#if CONFIG_IS_ENABLED(DM_USB_GADGET)
-int dm_usb_gadget_handle_interrupts(struct udevice *dev)
-{
-	return 0;
-}
-#else
+#if !CONFIG_IS_ENABLED(DM_USB_GADGET)
 int usb_gadget_register_driver(struct usb_gadget_driver *driver)
 {
 	struct sandbox_udc *dev = this_controller;