VeNum optimizations to libpng to improve PNG decode time

Set correct counter in neon routine for SUB filter type.
Enable Neon optimizations for all filter types and pixel depths.

(cherry picked from commit b912f64bc4bb174fc055cda58e303faaa640b8b1)

Conflicts:

	pngrutil.c
(cherry picked from commit fa02de5150971c6c0fa789a38bca32dece879d2b)

Change-Id: I444ba064fb978934e74b63f169440e9f1e4ac1bc

Conflicts:

	Android.mk
5 files changed