regulator: mem-acc: add snapshot of mem-acc-regulator driver

This is snapshot of the mem-acc-regulator driver as of msm-4.9
'commit 98cddae6cdce ("Merge "msm: camera: Fix media_entity
assignment")'.

Change-Id: I0c28466bfeb1763c34cbbe076fd14583d44cbf15
Signed-off-by: Tirupathi Reddy <tirupath@codeaurora.org>