Add codec long name, patch by Stefano Sabatini, stefano.sabatini-lala poste it.

Originally committed as revision 13154 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/mdec.c

@@ -267,5 +267,6 @@ AVCodec mdec_decoder = {
     decode_end,
     decode_frame,
     CODEC_CAP_DR1,
+    .long_name="Sony PlayStation MDEC (Motion DECoder)",
 };