msm: mdss: Add an extra write of zero to clear dsi-ack-err bit

In addition to writing 1 to clear dsi-ack-err bit, an extra write
of 0 is also needed to clear error bit completely.

CRs-fixed: 574066
Change-Id: Ib9df9fe5f993605372ced8766874fa00538f505a
Signed-off-by: Shivaraj Shetty <shivaraj@codeaurora.org>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
Signed-off-by: Chet Kener <Cl3Kener@gmail.com>
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.

Signed-off-by: Chet Kener <Cl3Kener@gmail.com>