regulator: tps65910: Convert to use regulator_map_voltage_ascend

All regulators have ascendant voltage list in this driver.
Some regulators have more than 200 supported voltages.
e.g.
For TPS65910_REG_VDD1 and TPS65910_REG_VDD2:
n_voltages = VDD1_2_NUM_VOLT_FINE * VDD1_2_NUM_VOLT_COARSE
           = 73 * 3
           = 219

Thus it worth converting to regulator_map_voltage_ascend rather than use
default regulator_map_voltage_iterate.

For consistent, convert all regulators to regulator_map_voltage_ascend.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/regulator/tps65910-regulator.c

@@ -748,6 +748,7 @@ static struct regulator_ops tps65910_ops_dcdc = {
 	.set_voltage_sel	= tps65910_set_voltage_dcdc_sel,
 	.set_voltage_time_sel	= regulator_set_voltage_time_sel,
 	.list_voltage		= tps65910_list_voltage_dcdc,
+	.map_voltage		= regulator_map_voltage_ascend,
 };
 
 static struct regulator_ops tps65910_ops_vdd3 = {
@@ -758,6 +759,7 @@ static struct regulator_ops tps65910_ops_vdd3 = {
 	.get_mode		= tps65910_get_mode,
 	.get_voltage		= tps65910_get_voltage_vdd3,
 	.list_voltage		= regulator_list_voltage_table,
+	.map_voltage		= regulator_map_voltage_ascend,
 };
 
 static struct regulator_ops tps65910_ops = {
@@ -769,6 +771,7 @@ static struct regulator_ops tps65910_ops = {
 	.get_voltage_sel	= tps65910_get_voltage_sel,
 	.set_voltage_sel	= tps65910_set_voltage_sel,
 	.list_voltage		= regulator_list_voltage_table,
+	.map_voltage		= regulator_map_voltage_ascend,
 };
 
 static struct regulator_ops tps65911_ops = {
@@ -780,6 +783,7 @@ static struct regulator_ops tps65911_ops = {
 	.get_voltage_sel	= tps65911_get_voltage_sel,
 	.set_voltage_sel	= tps65911_set_voltage_sel,
 	.list_voltage		= tps65911_list_voltage,
+	.map_voltage		= regulator_map_voltage_ascend,
 };
 
 static int tps65910_set_ext_sleep_config(struct tps65910_reg *pmic,