regulator: userspace-consumer: Handle regulator-output DT nodes

regulator: userspace-consumer: Handle regulator-output DT nodes

In addition to adding some fairly simple OF support code, we make some
slight adjustments to the userspace-consumer driver to properly
support use with regulator-output hardware:

 - We now do an exclusive get of the supply regulators so as to
   prevent regulator_init_complete_work from automatically disabling
   them.

 - Instead of assuming that the supply is initially disabled, we now
   query its state to determine the initial value of drvdata->enabled.

Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
Link: https://lore.kernel.org/r/20221031233704.22575-4-zev@bewilderbeest.net
Signed-off-by: Mark Brown <broonie@kernel.org>