regulator: tps65023: Convert to regulator_list_voltage_table

In current mapping table settings, min_uV/max_uV are always
equal to volt_table[0] and volt_table[table_len -1].
Thus remove min_uV and max_uV from struct tps_info.

The table based mapping with table_len == 1 means fixed voltage.
So we don't need fixed flag to differentiate if it is fixed or not.

This patch adds DCDC_FIXED_3300000_VSEL_table and DCDC_FIXED_1800000_VSEL_table
for fixed voltage cases. So we can convert tps65023_dcdc_ops to
regulator_list_voltage_table. This makes the code simpler.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>