msm_11ad: Add 11ad platform driver

Platform driver used to handle msm specific platform
requirement for 11ad chipset connected to msm platform
Takes care of platform support like:

- power switch through dedicated GPIO
- bus frequency voting
- SMMU attachment

This is a snapshot of commit Iee67284b71fab87c2b4a002d7e67d24ef83a9ac9
("Revert "msm_11ad: keep rf_clk3 on during wil6210 activity"").

Change-Id: I3d19fe54197c48b9d846b32c619bf5f2a14dbf5b
CRs-Fixed: 2143032
Signed-off-by: Alexei Avshalom Lazar <ailizaro@codeaurora.org>