rtc: rtc-ds1742: 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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-ds1742.c

@@ -219,7 +219,7 @@ static int ds1742_rtc_remove(struct platform_device *pdev)
 	return 0;
 }
 
-static struct of_device_id __maybe_unused ds1742_rtc_of_match[] = {
+static const struct of_device_id __maybe_unused ds1742_rtc_of_match[] = {
 	{ .compatible = "maxim,ds1742", },
 	{ }
 };