usb: musb: ux500: fix build warnings

This patch fixes the following build warnings:

drivers/usb/musb/ux500.c:346:12: warning: ‘ux500_suspend’ defined but
not used [-Wunused-function]
drivers/usb/musb/ux500.c:357:12: warning: ‘ux500_resume’ defined but not
used [-Wunused-function]
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/musb/ux500.c

@@ -342,7 +342,7 @@ static int ux500_remove(struct platform_device *pdev)
 	return 0;
 }
 
-#ifdef CONFIG_PM
+#ifdef CONFIG_PM_SLEEP
 static int ux500_suspend(struct device *dev)
 {
 	struct ux500_glue	*glue = dev_get_drvdata(dev);