CODEC_ID_XVID is not used anywhere, remove it at next major bump

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@22511 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavcodec/avcodec.h

@@ -125,7 +125,9 @@ enum CodecID {
     CODEC_ID_QDRAW,
     CODEC_ID_VIXL,
     CODEC_ID_QPEG,
+#if LIBAVCODEC_VERSION_MAJOR < 53
     CODEC_ID_XVID,
+#endif
     CODEC_ID_PNG,
     CODEC_ID_PPM,
     CODEC_ID_PBM,