rtc: make of_device_ids const

of_device_ids (i.e. compatible strings and the respective data) are not
supposed to change at runtime.  All functions working with of_device_ids
provided by <linux/of.h> work with const of_device_ids.  This allows to
mark all struct of_device_id below drivers/rtc const, too.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.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-mpc5121.c b/drivers/rtc/rtc-mpc5121.c
index dc4f142..3b965ad 100644
--- a/drivers/rtc/rtc-mpc5121.c
+++ b/drivers/rtc/rtc-mpc5121.c
@@ -401,7 +401,7 @@
 }
 
 #ifdef CONFIG_OF
-static struct of_device_id mpc5121_rtc_match[] = {
+static const struct of_device_id mpc5121_rtc_match[] = {
 	{ .compatible = "fsl,mpc5121-rtc", },
 	{ .compatible = "fsl,mpc5200-rtc", },
 	{},