rtc: rtc-rx4581: use devm_rtc_device_register()

devm_rtc_device_register() is device managed and makes cleanup paths
simpler.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-rx4581.c

@@ -273,8 +273,8 @@ static int rx4581_probe(struct spi_device *spi)
 	if (res != 0)
 		return res;
 
-	rtc = rtc_device_register("rx4581",
-				&spi->dev, &rx4581_rtc_ops, THIS_MODULE);
+	rtc = devm_rtc_device_register(&spi->dev, "rx4581",
+				&rx4581_rtc_ops, THIS_MODULE);
 	if (IS_ERR(rtc))
 		return PTR_ERR(rtc);
 
@@ -284,9 +284,6 @@ static int rx4581_probe(struct spi_device *spi)
 
 static int rx4581_remove(struct spi_device *spi)
 {
-	struct rtc_device *rtc = dev_get_drvdata(&spi->dev);
-
-	rtc_device_unregister(rtc);
 	return 0;
 }