usb: dwc2: Avoid leaving the error_debugfs label unused

The error_debugfs label is only used when either
CONFIG_USB_DWC2_PERIPHERAL or CONFIG_USB_DWC2_DUAL_ROLE is enabled. Add
the same #if to the error_debugfs label itself as the code which uses
this label already has.

This avoids the following compiler warning:
  warning: label ‘error_debugfs’ defined but not used [-Wunused-label]

Fixes: e1c08cf2 ("usb: dwc2: Add missing cleanups when usb_add_gadget_udc() fails")
Acked-by: Minas Harutyunyan <Minas.Harutyunyan@synopsys.com>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

drivers/usb/dwc2/platform.c

@@ -608,10 +608,13 @@ static int dwc2_driver_probe(struct platform_device *dev)
 #endif /* CONFIG_USB_DWC2_PERIPHERAL || CONFIG_USB_DWC2_DUAL_ROLE */
 	return 0;
 
+#if IS_ENABLED(CONFIG_USB_DWC2_PERIPHERAL) || \
+	IS_ENABLED(CONFIG_USB_DWC2_DUAL_ROLE)
 error_debugfs:
 	dwc2_debugfs_exit(hsotg);
 	if (hsotg->hcd_enabled)
 		dwc2_hcd_remove(hsotg);
+#endif
 error_drd:
 	dwc2_drd_exit(hsotg);