regulator: bd718x7: remove voltage change restriction from BD71847 LDOs

regulator: bd718x7: remove voltage change restriction from BD71847 LDOs

The BD71837 had a HW "feature" where changing the regulator output
voltages of other regulators but bucks 1-4 might cause spikes if
regulators were enabled. Thus SW prohibit voltage changes for other
regulators except for bucks 1-4 when regulator is enabled.

The HW colleagues did inadvertly fix this issue for BD71847 and
BD71850.

The power-good detection for LDOs can still cause false alarms if
LDO voltage is changed upwards when LDO is enabled.

Allow LDO voltage changes and disabe the power-good monioring for
the duration of the LDO voltage change and enable it after LDO
voltage has stabilized. ROHM HW colleagues measured the safety
limit of 1000uS for guaranteeing the voltage has stabilized. Let's
use that for starters and add confiurable stabilization wait-time
later if needed.

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Link: https://lore.kernel.org/r/20200513143921.GA22143@localhost.localdomain
Signed-off-by: Mark Brown <broonie@kernel.org>