regulator: twl6030: Fix voltage selection logic

The voltage selection logic for the twl6030 smps fails if
min:max is such that min < 1300mV and max > 1300mV although
this is in valid range for a regulator e.g. [x, 1350] where
x < 1300.
Fixing the voltage selection logic such that first it will
check for min_uV for a range and then calculated value will
be checked against max_uV.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>