dt-bindings: regulator: qcom,spmi: Document PM8909

dt-bindings: regulator: qcom,spmi: Document PM8909

Document the qcom,pm8909-regulators compatible together with the
necessary supply properties to allow interfacing via the hardware
regulator registers directly via SPMI. This is mainly intended for
debugging since the regulators are typically controlled via the RPM
firmware (qcom,rpm-pm8909-regulators compatible).

Signed-off-by: Stephan Gerhold <stephan.gerhold@kernkonzept.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230912-spmi-pm8909-v1-1-ba4b3bfaf87d@gerhold.net
Signed-off-by: Mark Brown <broonie@kernel.org>