Remove the preprocessor symbol WEBRTC_CODEC_PCM16 (it was always defined)

webrtc/modules/audio_coding/main/acm2/codec_manager.cc

 /*
  *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 104 matching lines @@
 
 bool IsPcmU(const CodecInst& codec) {
   return !STR_CASE_CMP(codec.plname, "pcmu");
 }
 
 bool IsPcmA(const CodecInst& codec) {
   return !STR_CASE_CMP(codec.plname, "pcma");
 }
 
 bool IsPcm16B(const CodecInst& codec) {
-  return
-#ifdef WEBRTC_CODEC_PCM16
-      !STR_CASE_CMP(codec.plname, "l16") ||
-#endif
-      false;
+  return !STR_CASE_CMP(codec.plname, "l16");
 }
 
 bool IsIlbc(const CodecInst& codec) {
   return
 #ifdef WEBRTC_CODEC_ILBC
       !STR_CASE_CMP(codec.plname, "ilbc") ||
 #endif
       false;
 }
 
@@ skipping 326 matching lines @@
     case 48000:
       return -1;
     default:
       FATAL() << sample_rate_hz << " Hz is not supported";
       return -1;
   }
 }
 
 }  // namespace acm2
 }  // namespace webrtc