regulator: lp8788-buck: Use regulator_map_voltage_ascend

All regulators have ascendant voltage list in this driver.
Use regulator_map_voltage_ascend for them.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/regulator/lp8788-buck.c

@@ -346,6 +346,7 @@ static unsigned int lp8788_buck_get_mode(struct regulator_dev *rdev)
 
 static struct regulator_ops lp8788_buck12_ops = {
 	.list_voltage = regulator_list_voltage_table,
+	.map_voltage = regulator_map_voltage_ascend,
 	.set_voltage_sel = lp8788_buck12_set_voltage_sel,
 	.get_voltage_sel = lp8788_buck12_get_voltage_sel,
 	.enable = regulator_enable_regmap,
@@ -358,6 +359,7 @@ static struct regulator_ops lp8788_buck12_ops = {
 
 static struct regulator_ops lp8788_buck34_ops = {
 	.list_voltage = regulator_list_voltage_table,
+	.map_voltage = regulator_map_voltage_ascend,
 	.set_voltage_sel = regulator_set_voltage_sel_regmap,
 	.get_voltage_sel = regulator_get_voltage_sel_regmap,
 	.enable = regulator_enable_regmap,