usb: gadget: atmel: fix build warnings

This patch fixes the following build warnings:

drivers/usb/gadget/udc/atmel_usba_udc.c:2207:12: warning:
‘usba_udc_suspend’ defined but not used [-Wunused-function] static int
usba_udc_suspend(struct device *dev)
drivers/usb/gadget/udc/atmel_usba_udc.c:2236:12: warning:
‘usba_udc_resume’ defined but not used [-Wunused-function] static int
usba_udc_resume(struct device *dev)
Signed-off-by: NFelipe Balbi <balbi@ti.com>

drivers/usb/gadget/udc/atmel_usba_udc.c

@@ -2203,7 +2203,7 @@ static int __exit usba_udc_remove(struct platform_device *pdev)
 	return 0;
 }
 
-#ifdef CONFIG_PM
+#ifdef CONFIG_PM_SLEEP
 static int usba_udc_suspend(struct device *dev)
 {
 	struct usba_udc *udc = dev_get_drvdata(dev);