msm_fb: display: add blt condition check at video/lcdc off

Blt mode may be enabled during system suspend. Need to make
sure blt overlay done  before turn off video/lcdc timig generator.

(cherry picked from commit 4b251d6f0067af78a0a424af5054747cc38a0904)

Change-Id: If07d51bdad94b8098d50bb8be0ce4a1d758ec212
Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
msm_fb: display: Send vsync events using sysfs for MDP4 targets

Replace sending of vsync timestamp using uevents with sysfs entry
as uevent result in increase in power numbers due to broadcast in
nature. Also, for smart panel, wait4vsync is removed.

Change-Id: Id101d3f435a23ee941d679136b670a0b72f1abbc
Signed-off-by: Mayank Chopra <makchopra@codeaurora.org>
Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
Signed-off-by: Siddhartha Agrawal <agrawals@codeaurora.org>
msm_fb: display: Make sysfs read request interruptible

Change blocking sysfs read request to be interruptible and protect
vsync timestamp value to prevent corruption.

Change-Id: I510d84134b0ab70d17729e8c53c91fa926035142
Signed-off-by: Mayank Chopra <makchopra@codeaurora.org>
Signed-off-by: Praveena Pachipulusu <pveena@codeaurora.org>
Signed-off-by: Satish Kamuju <skamuj@codeaurora.org>