rtc: rtc-hym8563: make of_device_id array const

Make of_device_id array const, because all OF functions handle it as
const.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Heiko Stbner <heiko@sntech.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/rtc/rtc-hym8563.c b/drivers/rtc/rtc-hym8563.c
index e5f13c4..e3290ab 100644
--- a/drivers/rtc/rtc-hym8563.c
+++ b/drivers/rtc/rtc-hym8563.c
@@ -585,7 +585,7 @@
 };
 MODULE_DEVICE_TABLE(i2c, hym8563_id);
 
-static struct of_device_id hym8563_dt_idtable[] = {
+static const struct of_device_id hym8563_dt_idtable[] = {
 	{ .compatible = "haoyu,hym8563" },
 	{},
 };