reduce PB size from 2MB to 512KB

this allows us to enable h/w acceleration on low-end
devices while keeping memory usage down.

Bug: 6557760
Change-Id: I8af2de3038dc2579360b8b73aa452cb7a0e506a9
Fix QCOM_BSP ifdef

Change-Id: Ibeee2edadcf03b92f31cf3af3c0be0e2e0af023d
sf:  Add dirtyRect information to SF dumpsys

Display dirtyRect information generated for each layer in
SurfaceFlinger Dumpsys.

Change-Id: Ie60f4bf67bc28af0fcce006c166d8ae4ed4985e8
sf: Use Dirty Rect optimization in "Show Surface Updates" setting

When "Show Surface Updates" setting is ON in developer options, flash the
updating part (union dirty rect) instead of full layers when
GPU Tiled DR optimization is ON.

Change-Id: Id280cc2a22d46cc6539316d6dd0856e328c14c9e
CRs-Fixed: 679386