rtc: ds1337: fix compatible string typo

The driver supports the ds1339 as well, which was probably intended by
the author but prevented by a typo. Fix the typo.

Signed-off-by: Clemens Gruber <clemens.gruber@pqgruber.com>
diff --git a/drivers/rtc/ds1337.c b/drivers/rtc/ds1337.c
index 4986c96..486c01f 100644
--- a/drivers/rtc/ds1337.c
+++ b/drivers/rtc/ds1337.c
@@ -306,7 +306,7 @@
 static const struct udevice_id ds1337_rtc_ids[] = {
 	{ .compatible = "ds1337" },
 	{ .compatible = "ds1338" },
-	{ .compatible = "ds1338" },
+	{ .compatible = "ds1339" },
 	{ }
 };