Forward-port surface dithering from CM10.1

This allows the use of 16-bit color displays without excessive color
banding;

Change-Id: Icb469b9cb4beb686516c60bb576dbd0a73f505e0
Don't use fence sync for qcom legacy

Signed-off-by: Michael Bestas <mikeioannina@gmail.com>

Change-Id: Ifecc7af579bfde9d0a7daaaf528ea0773ce6ceb2
surfaceflinger: enable EGL_NEEDS_FNW for qcom legacy

Signed-off-by: Michael Bestas <mikeioannina@gmail.com>

Change-Id: Ia6df94e8380062d646e29f293e5dc768e8a138e7