Device trees for newer SoCs avoid defining the regulator nodes directly
in the SoC device tree (here: msm8916.dtsi). The reason for this is that
theoretically it is possible to combine the SoC with a different PMIC,
or to use all the regulators in a board-specific way.

Therefore let's remove those from the SoC include (msm8916.dtsi).

In practice, pretty much all MSM8916 boards were combined with PM8916,
and use the regulators in similar ways. After looking at many different
MSM8916 boards (mostly smartphones and tablets), I haven't seen a single
device that isn't using the same regulators for components integrated
into the SoC.

If all boards end up defining all regulators and supplies in the same way
then it is useful to have an include for that, so we can avoid duplicating
it everywhere. If there is really a super special board that does it
differently it could just override some properties or avoid using the
include altogether.

This patch moves the regulator and common supply definitions to
a new include called "msm8916-pm8916.dtsi".

This is also going to be useful when introducing CPR (Core Power
Reduction) later because we can configure the CPU regulator
(pm8916_spmi_s2) for all devices in this common include.
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20200720085406.6716-8-stephan@gerhold.netSigned-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>