rtc: s5m: switch to devm_rtc_allocate_device

Switch to devm_rtc_allocate_device/devm_rtc_register_device, this allows
for further improvement of the driver.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20210804104133.5158-1-alexandre.belloni@bootlin.com

drivers/rtc/rtc-s5m.c

@@ -788,12 +788,16 @@ static int s5m_rtc_probe(struct platform_device *pdev)
 
 	device_init_wakeup(&pdev->dev, 1);
 
-	info->rtc_dev = devm_rtc_device_register(&pdev->dev, "s5m-rtc",
-						 &s5m_rtc_ops, THIS_MODULE);
-
+	info->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
 	if (IS_ERR(info->rtc_dev))
 		return PTR_ERR(info->rtc_dev);
 
+	info->rtc_dev->ops = &s5m_rtc_ops;
+
+	err = devm_rtc_register_device(info->rtc_dev);
+	if (err)
+		return err;
+
 	if (!info->irq) {
 		dev_info(&pdev->dev, "Alarm IRQ not available\n");
 		return 0;