Remove AMR format parameter from AudioCoder in utility

The parameter was never used.

BUG=webrtc:3520

Review URL: https://codereview.webrtc.org/1365283002

Cr-Commit-Position: refs/heads/master@{#10095}
diff --git a/webrtc/modules/utility/source/file_player_impl.cc b/webrtc/modules/utility/source/file_player_impl.cc
index 8c94caa..29ad9e3 100644
--- a/webrtc/modules/utility/source/file_player_impl.cc
+++ b/webrtc/modules/utility/source/file_player_impl.cc
@@ -389,7 +389,7 @@
         return -1;
     }
     if( STR_CASE_CMP(_codec.plname, "L16") != 0 &&
-        _audioDecoder.SetDecodeCodec(_codec,AMRFileStorage) == -1)
+        _audioDecoder.SetDecodeCodec(_codec) == -1)
     {
         LOG(LS_WARNING) << "SetUpAudioDecoder() codec " << _codec.plname
                         << " not supported.";