drm: msm: dsi-staging: add support for DSI clock manager

Add support for DSI clock manager driver. This includes
refactor of the DSI power module, ULPS, PHY clamping,
DSI controller/PHY re-initialisation, and adds support
for enable/disable of DSI clocks during static screen.
The DSI clock manager maintains three state of the DSI
clocks namely ON/OFF/ECG.

CRs-Fixed: 2008002
Change-Id: I15bcf8531be6596c4a9dc52690c4971de46f387d
Signed-off-by: Padmanabhan Komanduru <pkomandu@codeaurora.org>
Signed-off-by: Shashank Babu Chinta Venkata <sbchin@codeaurora.org>