rpmh-regulators: Update rpmh-regulator driver and

Merge series from Kamal Wadhwa <kamal.wadhwa@oss.qualcomm.com>:

This series contains patches to update rpmh-regulator driver and
dt-bindings for supporting the PMIC voltage regulators present on the
boards with Qualcomm's next gen compute SoC - Glymur.

Device tree changes aren't part of this series and will be posted
separately after the official announcement of the Glymur SoC.