regulator: palmas: Fix min_uV for LDO8 tracking mode

When SMPS45 is set to off and LDO8 tracking is enabled, the output voltage can
be set from 0.45 to 1.65 V. Thus set min_uV to be 450000.

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