hwmon: (pwm-fan, vexpress) 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: Guenter Roeck <linux@roeck-us.net>
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index 4170728..31d793b 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -322,7 +322,7 @@
 
 static SIMPLE_DEV_PM_OPS(pwm_fan_pm, pwm_fan_suspend, pwm_fan_resume);
 
-static struct of_device_id of_pwm_fan_match[] = {
+static const struct of_device_id of_pwm_fan_match[] = {
 	{ .compatible = "pwm-fan", },
 	{},
 };