Add optimized S16_opaque_D32_nofilter_DX blitter.

Adds an NEON optimized version of Skia sample blitter
S16_opaque_D32_nofilter_DX when running unscaled.
Used when scrolling UI lists.

Change-Id: I7a212f2e50aba3244aab237937395af02abe81a9
Signed-off-by: Henrik Smiding <henrik.smiding@stericsson.com>
Signed-off-by: Patrik Ryd <patrik.ryd@stericsson.com>