rtc: m48t86: add DT support for m48t86

Add OF ID match table.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/lkml/20230601054549.10843-12-nikita.shubin@maquefel.me/
Signed-off-by: Nikita Shubin <nikita.shubin@maquefel.me>
Link: https://lore.kernel.org/r/20230823-m48t86_device_tree-v2-2-21ff275f949d@maquefel.me
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-m48t86.c

@@ -11,6 +11,7 @@
  */
 
 #include <linux/module.h>
+#include <linux/mod_devicetable.h>
 #include <linux/rtc.h>
 #include <linux/platform_device.h>
 #include <linux/bcd.h>
@@ -269,9 +270,16 @@ static int m48t86_rtc_probe(struct platform_device *pdev)
 	return 0;
 }
 
+static const struct of_device_id m48t86_rtc_of_ids[] = {
+	{ .compatible = "st,m48t86" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, m48t86_rtc_of_ids);
+
 static struct platform_driver m48t86_rtc_platform_driver = {
 	.driver		= {
 		.name	= "rtc-m48t86",
+		.of_match_table = m48t86_rtc_of_ids,
 	},
 	.probe		= m48t86_rtc_probe,
 };