rtc: pcf2123: convert to devm_rtc_allocate_device

This allows further improvement of the driver. Also remove the unecessary
error string as the core will already display error messages.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20190819182656.29744-7-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-pcf2123.c

@@ -408,17 +408,12 @@ static int pcf2123_probe(struct spi_device *spi)
 			(spi->max_speed_hz + 500) / 1000);
 
 	/* Finalize the initialization */
-	rtc = devm_rtc_device_register(&spi->dev, pcf2123_driver.driver.name,
-			&pcf2123_rtc_ops, THIS_MODULE);
-
-	if (IS_ERR(rtc)) {
-		dev_err(&spi->dev, "failed to register.\n");
+	rtc = devm_rtc_allocate_device(&spi->dev);
+	if (IS_ERR(rtc))
 		return PTR_ERR(rtc);
-	}
 
 	pcf2123->rtc = rtc;
 
-
 	/* Register alarm irq */
 	if (spi->irq > 0) {
 		ret = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
@@ -435,7 +430,12 @@ static int pcf2123_probe(struct spi_device *spi)
 	 * support to this driver to generate interrupts more than once
 	 * per minute.
 	 */
-	pcf2123->rtc->uie_unsupported = 1;
+	rtc->uie_unsupported = 1;
+	rtc->ops = &pcf2123_rtc_ops;
+
+	ret = rtc_register_device(rtc);
+	if (ret)
+		return ret;
 
 	return 0;
 }