regulator: bd718x7: Suopport configuring UVP/OVP state

The ROHM BD71837/47/50/78 do support enabling/disabling the under/over
voltage protection. Add support for enabling/disabling the protection
according to the device-tree information.

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Link: https://lore.kernel.org/r/20210705105416.GA1189560@localhost.localdomain


Signed-off-by: Mark Brown <broonie@kernel.org>