ARM: dts: msm: switch to RPM control for most regulators on MSM8916

Convert most of the PM8916 qpnp-regulator devices to a
rpm-smd-regulator devices.  This ensures that requests made for
these regulators are aggregated by the RPM processor along with
the requests from other processors.

PM8916 SMPS 2 should not be converted to an rpm-smd-regulator device
because it is used and controlled by the CPR regulator device.
The S2 regulator powers the application processor cores.

Lower the value specified for regulator-min-microvolt for the
following regulators:
- regulators L3 (VDD_MX) and S1 (VDD_CX) since the RPM is capable
  of enforcing system-wide constraints on their final output voltages.
- regulator S3 since clients connected to this regulator can operate
  at 1.2 V.
- regulator S4 since clients connected to this regulator can operate
  at 1.8 V.
- regulator L8 since clients connected to this regulator can operate
  at 2.85 V.

Change-Id: Ia8ddc5dc80c17e31db3da09a21082d74585f54c4
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>