Add Neon versions of memset32 and memset16

Patch by pgalizia (of codeaurora.org)

(Note: I don't read ARM and I didn't manage to find a reviewer for the
ARM assembly code so this is landing somewhat unreviewed.)

http://codereview.appspot.com/1157045/show

git-svn-id: http://skia.googlecode.com/svn/trunk@573 2bbb7eff-a529-9590-31e7-b0007b416f81
3 files changed