Restore cutil memsetX functions for Cortex-A9.

Summary:
Restores usage of memset16/32 functions from Android's libcutil
library for platforms running Cortex-A9, since non-Neon
is usually faster.

Change-Id: I7b55e08f9dc4a403caaa8b1f90e0c0eea0d73542
Signed-off-by: Henrik Smiding <henrik.smiding@stericsson.com>
Signed-off-by: Patrik Ryd <patrik.ryd@stericsson.com>

Test Plan: skia benchtest

Reviewers: randall.rushing, synergy

Reviewed By: synergy

Differential Revision: http://review.codefirex.com/D529