mfd: as3711: Make of_device_id array const

Array of struct of_device_id may be be const as expected by
of_match_table field.
Signed-off-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

drivers/mfd/as3711.c

@@ -114,7 +114,7 @@ static const struct regmap_config as3711_regmap_config = {
 };
 
 #ifdef CONFIG_OF
-static struct of_device_id as3711_of_match[] = {
+static const struct of_device_id as3711_of_match[] = {
 	{.compatible = "ams,as3711",},
 	{}
 };