msm: mdss: Fix issues in gamma interface

Protect access to panel command struct by mutex,
this should help with ULPS stability during panel
on as well.  Also, remove the broken debug FS.

Change-Id: I975838eb4bc7fbf07f48c41dfe9a783c495e0afc
msm: mdss: Debug log for assertive display inputs

Log updates to ambient and strength inputs on assertive display.

Change-Id: Ie96baf2cb6f4af4c74e154322b870f4eb58cbfb2
Signed-off-by: Carl Vanderlip <carlv@codeaurora.org>
msm: mdss: Update BL on first AD update

First AD update is not updating with current backlight value. Initialize
last_bl variable so that first request updates backlight along with user
specified input.

Change-Id: I453e5448229dbddb6204c0a654c267e1540c59a3
Signed-off-by: Carl Vanderlip <carlv@codeaurora.org>