Add MPEG FourCC for MPEG-2 video.

Originally committed as revision 5391 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/avienc.c

@@ -140,6 +140,7 @@ const CodecTag codec_bmp_tags[] = {
     { CODEC_ID_MPEG1VIDEO, MKTAG('m', 'p', 'g', '1') },
     { CODEC_ID_MPEG1VIDEO, MKTAG('m', 'p', 'g', '2') },
     { CODEC_ID_MPEG2VIDEO, MKTAG('m', 'p', 'g', '2') },
+    { CODEC_ID_MPEG2VIDEO, MKTAG('M', 'P', 'E', 'G') },
     { CODEC_ID_MPEG1VIDEO, MKTAG('P', 'I', 'M', '1') },
     { CODEC_ID_MPEG1VIDEO, MKTAG('V', 'C', 'R', '2') },
     { CODEC_ID_MPEG1VIDEO, 0x10000001 },