regulator: Introduce Maxim MAX20411 Step-Down converter

Introduce a driver to control the Maxim MAX20411 family of
high-efficiency, syncrhonous step-down converters.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
Link: https://lore.kernel.org/r/20230124184440.1421074-3-quic_bjorande@quicinc.com


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