msm: mdss: Block postprocessing updates during DTM

When calibration tool requests the fb driver to enter in
Display Tuning Mode (DTM), PostProcessing blocks should
not update the HSIC, Memory color, Six Zone colors, etc.
Updating them during DTM conflicts the update from
calibration tool.

Change-Id: I11fcac57a651581d85e771911f83b2fdd9c3c681
Signed-off-by: Dhaval Patel <pdhaval@codeaurora.org>
msm: mdss: Add update notify for backlight change in static screen

Previously, the change of backlight sysfs node value will not trigger
notify updates if display is in static screen case. This will cause
delay or wrong configuration for assertive display. This patch fixes
the above issue by adding an update notify if backlight changes when
there are no display updates.

Change-Id: I1475896214a50dc1fa71739aa751b2e626d27adb
Signed-off-by: Ping Li <quicpingli@codeaurora.org>