dt-bindings: regulator: Regulator driver for the PM8008 PMIC

This is a snapshot of the regulator PM8008 Documentation as of
msm-4.14 'commit 1e5b6117 (Merged: Merge "ARM: dts: msm:
Add tpdm lpass for sdmmagpie")'.

Change-Id: Iffaf820b4549adc40b02073a140cb8f2722c1eac
Signed-off-by: Umang Agrawal <uagrawal@codeaurora.org>