MFD: ucb1x00-core: Add CONFIG_PM_SLEEP to suspend/resume

Add CONFIG_PM_SLEEP to suspend/resume functions to fix the build
warnings when CONFIG_PM_SLEEP is not selected. This is because
sleep PM callbacks defined by SET_SYSTEM_SLEEP_PM_OPS are only used
when the CONFIG_PM_SLEEP is enabled.

drivers/mfd/ucb1x00-core.c:672:12: warning: 'ucb1x00_suspend' defined but not used [-Wunused-function]
drivers/mfd/ucb1x00-core.c:704:12: warning: 'ucb1x00_resume' defined but not used [-Wunused-function]
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

drivers/mfd/ucb1x00-core.c

@@ -669,6 +669,7 @@ void ucb1x00_unregister_driver(struct ucb1x00_driver *drv)
 	mutex_unlock(&ucb1x00_mutex);
 }
 
+#ifdef CONFIG_PM_SLEEP
 static int ucb1x00_suspend(struct device *dev)
 {
 	struct ucb1x00_plat_data *pdata = dev_get_platdata(dev);
@@ -736,6 +737,7 @@ static int ucb1x00_resume(struct device *dev)
 	mutex_unlock(&ucb1x00_mutex);
 	return 0;
 }
+#endif
 
 static const struct dev_pm_ops ucb1x00_pm_ops = {
 	SET_SYSTEM_SLEEP_PM_OPS(ucb1x00_suspend, ucb1x00_resume)