Neon version of FilterAdaptation()

The performance gain on a Nexus 7 reported by audioproc is ~5.2%.

The output is bit exact.

Measured total of 15% speed gain on N7 compared to C.

R=bjornv@webrtc.org, cd@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/17699004

Patch from Scott LaVarnway <slavarnw@gmail.com>.

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6480 4adac7df-926f-26a2-2b94-8c16560cd09d