regulator: core: return zero for selectors lower than linear_min_sel

regulator: core: return zero for selectors lower than linear_min_sel

Selectors lower than linear_min_sel should not be considered invalid.
Thus return zero in case _regulator_list_voltage(),
regulator_list_hardware_vsel() or regulator_list_voltage_table()
receives such selectors as argument.

Fixes: bdcd1177578c ("regulator: core: validate selector against linear_min_sel")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/1606325147-606-1-git-send-email-claudiu.beznea@microchip.com
Signed-off-by: Mark Brown <broonie@kernel.org>