iio: 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>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/drivers/iio/common/ssp_sensors/ssp_dev.c b/drivers/iio/common/ssp_sensors/ssp_dev.c
index 55a90082..9a40097 100644
--- a/drivers/iio/common/ssp_sensors/ssp_dev.c
+++ b/drivers/iio/common/ssp_sensors/ssp_dev.c
@@ -437,7 +437,7 @@
 }
 
 #ifdef CONFIG_OF
-static struct of_device_id ssp_of_match[] = {
+static const struct of_device_id ssp_of_match[] = {
 	{
 		.compatible	= "samsung,sensorhub-rinato",
 		.data		= &ssp_rinato_info,