it is not necessary to display the decoder name, as av_log() automatically prints the context

Originally committed as revision 22023 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/mmvideo.c

@@ -60,7 +60,7 @@ static av_cold int mm_decode_init(AVCodecContext *avctx)
 
     s->frame.reference = 1;
     if (avctx->get_buffer(avctx, &s->frame)) {
-        av_log(s->avctx, AV_LOG_ERROR, "mmvideo: get_buffer() failed\n");
+        av_log(s->avctx, AV_LOG_ERROR, "get_buffer() failed\n");
         return -1;
     }