arm64: dts: qcom: sdm660-xiaomi-lavender: Add RPM and fixed regulators

Add most of the RPM PM660/PM660L regulators and the fixed ones,
defining the common electrical part of this platform.

Signed-off-by: Dang Huynh <danct12@riseup.net>
Reviewed-by: Caleb Connolly <caleb@connolly.tech>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20211120214227.779742-4-danct12@riseup.net