regulator: max77686: Make regulator_desc array const

The regulator_register() expects array of 'regulator_desc' to be const.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/max77686.c

@@ -350,7 +350,7 @@ static struct regulator_ops max77686_buck_dvs_ops = {
 			<< MAX77686_OPMODE_BUCK234_SHIFT,		\
 }
 
-static struct regulator_desc regulators[] = {
+static const struct regulator_desc regulators[] = {
 	regulator_desc_ldo1_low(1),
 	regulator_desc_ldo_low(2),
 	regulator_desc_ldo(3),