correct comment about seek function

Originally committed as revision 8797 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/mxf.c

@@ -991,7 +991,7 @@ static int mxf_probe(AVProbeData *p) {
     return 0;
 }
 
-/* rudimentary binary seek */
+/* rudimentary byte seek */
 /* XXX: use MXF Index */
 static int mxf_read_seek(AVFormatContext *s, int stream_index, int64_t sample_time, int flags)
 {