Refactor common_audio/vad: Removed usage of macro WEBRTC_SPL_MUL_16_16()

BUG=3348,3353
TESTED=Locally on Mac and trybots
R=kwiberg@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/34719004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@8152 4adac7df-926f-26a2-2b94-8c16560cd09d
3 files changed