Revert "libhwcomposer: print a log if there is any delay in vsync read."

This reverts commit 624cef4052af2995c6360bca71f6acbf529cbe3a.
This log is misleading as it does not print the actual vsync time
when vsync is disabled then enabled. It prints accumulated time
from vsync disable to next vsync enable.

Change-Id: I0ca3c9bc1e07a048e4563254ab83a3dd6b8c55ec
hwc: Remove need for intermediate buffer for c2d composition

A-Family device NON PRO 8960 uses copybit composition. The
intermediate buffers allocated are not needed when we can
compose onto fb frame.

Change-Id: I13fd2deb328a3ef4b6738cfe7030fe67ea7bd6c6
libhwcomposer: Disable mixed mode on plane alpha downscaling

When mixed mode is enabled while a layer contains
plane alpha and requires downscaling, part of the
layer containing plane alpha is exhibited as black area.

Change-Id: If47fa773846cbead3d6b2cad06ea80872233a908