arm64: dts: qcom: Add 8x16 chipset SPMI PMIC's nodes

arm64: dts: qcom: Add 8x16 chipset SPMI PMIC's nodes

PM9816 has 2 SPMI devices per physical package. Add PMIC configuration
nodes including sub-function device nodes and include them in boards,
which are using 8x16 based chipset.

PM9816 sub-function devices include:

* GPIO block, with 4 pins
* MPP block, with 4 pins
* Volatage ADC (VADC), with multiple inputs
* Thermal sensor device, which is using on chip VADC
  channel report PMIC die temperature.
* Power key device, which is responsible for clean system
  reboot or shutdown
* RTC device

Signed-off-by: Ivan T. Ivanov <ivan.ivanov@linaro.org>
Signed-off-by: Kumar Gala <galak@codeaurora.org>