regulator: as3722: Make 0 a valid selector

As of commit 064d5cd1 (regulator: core: Fix the init of DT defined
fixed regulators) the regulator core tries to query the current voltage
of a regulator when applying constraints. This exposes a bug in the
AS3722 regulator driver which fails to read the voltage of disabled
regulators. The reason is that the hardware is programmed to a selector
of 0, but none of the voltage tables include 0 as a valid selector. The
datasheets indicate that 0 is a valid selector when the regulators are
powered off.

To fix this, add a range including selector 0 to the voltage tables.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Mark Brown <broonie@linaro.org>