ADPCM: remove unreachable break statement after return

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@19312 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavcodec/adpcm.c

@@ -191,7 +191,6 @@ static av_cold int adpcm_encode_init(AVCodecContext *avctx)
         break;
     default:
         return -1;
-        break;
     }
 
     avctx->coded_frame= avcodec_alloc_frame();