power: constify of_device_id array

of_device_id is always used as const.
(See driver.of_match_table and open firmware functions)

Signed-off-by: Fabian Frederick <fabf@skynet.be>

[for vexpress]
Acked-by: Sudeep Holla <sudeep.holla@arm.com>

Signed-off-by: Sebastian Reichel <sre@kernel.org>
diff --git a/drivers/power/reset/st-poweroff.c b/drivers/power/reset/st-poweroff.c
index 27383de..a488877 100644
--- a/drivers/power/reset/st-poweroff.c
+++ b/drivers/power/reset/st-poweroff.c
@@ -97,7 +97,7 @@
 	.priority = 192,
 };
 
-static struct of_device_id st_reset_of_match[] = {
+static const struct of_device_id st_reset_of_match[] = {
 	{
 		.compatible = "st,stih415-restart",
 		.data = (void *)&stih415_reset,