ARM: dts: msm: allow mode control for VRM managed LDO regulators on SDM845

Add lower power mode (LPM) and high power mode (HPM) as the
supported modes for all PMIC LDO regulators managed via the RPMh
VRM accelerator.  Specify 10 mA as the threshold between LPM and
HPM.  This allows LDO consumers to change the operating mode of
the LDO via load current requests.

Change-Id: Ib380645b65eded8b66bce84a78b9c4a8f121d702
Signed-off-by: David Collins <collinsd@codeaurora.org>