cosmetics: Fix mxf codec long name.

Originally committed as revision 14256 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/mxf.c

@@ -1064,7 +1064,7 @@ static int mxf_read_seek(AVFormatContext *s, int stream_index, int64_t sample_ti
 
 AVInputFormat mxf_demuxer = {
     "mxf",
-    NULL_IF_CONFIG_SMALL("MXF format"),
+    NULL_IF_CONFIG_SMALL("Material eXchange Format"),
     sizeof(MXFContext),
     mxf_probe,
     mxf_read_header,