regulator: max77693: Constify regulator_ops

Static struct regulator_ops is not modified so can be made const for
code safeness.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/max77693-regulator.c

@@ -150,7 +150,7 @@ static struct regulator_ops max77693_safeout_ops = {
 	.set_voltage_sel	= regulator_set_voltage_sel_regmap,
 };
 
-static struct regulator_ops max77693_charger_ops = {
+static const struct regulator_ops max77693_charger_ops = {
 	.is_enabled		= regulator_is_enabled_regmap,
 	.enable			= regulator_enable_regmap,
 	.disable		= regulator_disable_regmap,