arm64: dts: qcom: sa8775p: add support for the on-board PMICs

Add a new .dtsi file for sa8775p PMICs and add the four PMICs interfaced
to the SoC via SPMI. Enable the PMICs for sa8775p-ride.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230327125316.210812-8-brgl@bgdev.pl