Add device tree support for m41t93 rtc by adding of_match_table.
Define compatible string - "st,m41t93" which can be used to instantiate
this rtc device via DT node.

Signed-off-by: Akhilesh Patil <akhilesh@ee.iitb.ac.in>
---
 drivers/rtc/rtc-m41t93.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/rtc/rtc-m41t93.c b/drivers/rtc/rtc-m41t93.c
index 9444cb5f5190..4e803ff0ce49 100644
--- a/drivers/rtc/rtc-m41t93.c
+++ b/drivers/rtc/rtc-m41t93.c
@@ -191,9 +191,16 @@ static int m41t93_probe(struct spi_device *spi)
 	return 0;
 }
 
+static const struct of_device_id m41t93_dt_match[] = {
+	{ .compatible = "st,m41t93" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, m41t93_dt_match);
+
 static struct spi_driver m41t93_driver = {
 	.driver = {
 		.name	= "rtc-m41t93",
+		.of_match_table = m41t93_dt_match,
 	},
 	.probe	= m41t93_probe,
 };
-- 
2.34.1