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/coder.cc b/webrtc/modules/utility/source/coder.cc
index 1baeaef..4ec5f9b 100644
--- a/webrtc/modules/utility/source/coder.cc
+++ b/webrtc/modules/utility/source/coder.cc
@@ -29,8 +29,7 @@
 {
 }
 
-int32_t AudioCoder::SetEncodeCodec(const CodecInst& codecInst,
-                                   ACMAMRPackingFormat amrFormat)
+int32_t AudioCoder::SetEncodeCodec(const CodecInst& codecInst)
 {
     if(_acm->RegisterSendCodec((CodecInst&)codecInst) == -1)
     {
@@ -39,8 +38,7 @@
     return 0;
 }
 
-int32_t AudioCoder::SetDecodeCodec(const CodecInst& codecInst,
-                                   ACMAMRPackingFormat amrFormat)
+int32_t AudioCoder::SetDecodeCodec(const CodecInst& codecInst)
 {
     if(_acm->RegisterReceiveCodec((CodecInst&)codecInst) == -1)
     {