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>

drivers/rtc/rtc-hym8563.c

@@ -585,7 +585,7 @@ static const struct i2c_device_id hym8563_id[] = {
 };
 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" },
 	{},
 };