regulator: Add protection limit properties

Support specifying protection/error/warning limits for regulator
over current, over temperature and over/under voltage.

Most of the PMICs support only "protection" feature but few
setups do also support error/warning level indications.

On many ICs most of the protection limits can't actually be set.
But for example the ampere limit for over-current protection on ROHM
BD9576 can be configured - or feature can be completely disabled.

Provide limit setting for all protections/errors for the sake of
the completeness and do that using own properties for all so that
not all users would need to set all levels when only one or few are
supported.

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/ae2c6056d5ed1334912d27e736d23c9151065433.1622628333.git.matti.vaittinen@fi.rohmeurope.com


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