rtc: m48t86: call rtc_nvmem_register()

Call rtc_nvmem_register instead of letting the core do it and stop using
the nvmem_config member of struct rtc_device.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-m48t86.c

@@ -266,13 +266,14 @@ static int m48t86_rtc_probe(struct platform_device *pdev)
 	info->rtc->ops = &m48t86_rtc_ops;
 
 	m48t86_nvmem_cfg.priv = &pdev->dev;
-	info->rtc->nvmem_config = &m48t86_nvmem_cfg;
 	info->rtc->nvram_old_abi = true;
 
 	err = rtc_register_device(info->rtc);
 	if (err)
 		return err;
 
+	rtc_nvmem_register(info->rtc, &m48t86_nvmem_cfg);
+
 	/* read battery status */
 	reg = m48t86_readb(&pdev->dev, M48T86_D);
 	dev_info(&pdev->dev, "battery %s\n",