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 <[e-mail]>
Reviewed-by: Chanwoo Choi <[e-mail]>
Signed-off-by: Mark Brown <[e-mail]>

drivers/regulator/max77693-regulator.c

···
 	.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,