regulator: tps65910: Remove unused min_uV and max_uV from struct tps_info

The min_uV and max_uV fields of struct tps_info are not used in the code.
For the case voltage_table is provided, the min_uV and max_uV are the same
values as volt_table[0] and volt_table[n_voltages -1].
For the case voltage_table is not available, having the min_uV and max_uV seems
misleading. Current code uses equations to get the voltage value in this case,
but these equations do not use the min_uV and max_uV fields of struct tps_info.

Thus this patch removes the min_uV and max_uV fields from struct tps_info.

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