libtwolame: fix stupid bug

Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavcodec/libtwolame.c

@@ -176,7 +176,7 @@ static const AVClass libtwolame_class = {
 AVCodec ff_libtwolame_encoder = {
     .name                  = "libtwolame",
     .type                  = AVMEDIA_TYPE_AUDIO,
-    .id                    = AV_CODEC_ID_MP3,
+    .id                    = AV_CODEC_ID_MP2,
     .priv_data_size        = sizeof(TWOLAMEContext),
     .init                  = twolame_encode_init,
     .encode2               = twolame_encode_frame,