NetEq4: Removing templatization for AudioMultiVector

This saves approx 6% runtime for neteq4_speed_test.
$ time out/Release/neteq4_speed_test --runtime_ms=50000000

BUG=1363
R=minyue@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/2320006

git-svn-id: http://webrtc.googlecode.com/svn/trunk@4885 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/modules/audio_coding/neteq4/background_noise.cc b/webrtc/modules/audio_coding/neteq4/background_noise.cc
index f306466..2dfb3c1 100644
--- a/webrtc/modules/audio_coding/neteq4/background_noise.cc
+++ b/webrtc/modules/audio_coding/neteq4/background_noise.cc
@@ -38,7 +38,7 @@
   // Keep _bgnMode as it is.
 }
 
-void BackgroundNoise::Update(const AudioMultiVector<int16_t>& input,
+void BackgroundNoise::Update(const AudioMultiVector& input,
                              const PostDecodeVad& vad) {
   if (vad.running() && vad.active_speech()) {
     // Do not update the background noise parameters if we know that the signal