regulator: Add regulator-output binding

This describes a power output supplied by a regulator, such as a
power outlet on a power distribution unit (PDU).

Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20221031233704.22575-3-zev@bewilderbeest.net


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