Add FVFW and fvfw since ffdshow seems to offer that as an option when encoding...

Add FVFW and fvfw since ffdshow seems to offer that as an option when encoding mpeg 4 video. This might fix a few cases where videos weren't decoded by VLC.

modules/codec/ffmpeg/ffmpeg.c

@@ -645,6 +645,10 @@ static struct
       VIDEO_ES, "Jomigo HDX4 (MPEG-4 Video)" },
     { VLC_FOURCC('S','M','P','4'), CODEC_ID_MPEG4,
       VIDEO_ES, "Samsung SMP4 (MPEG-4 Video)" },
+    { VLC_FOURCC('f','v','f','w'), CODEC_ID_MPEG4,
+      VIDEO_ES, "FFmpeg MPEG-4" },
+    { VLC_FOURCC('F','V','F','W'), CODEC_ID_MPEG4,
+      VIDEO_ES, "FFmpeg MPEG-4" },
 
     /* MSMPEG4 v1 */
     { VLC_FOURCC('D','I','V','1'), CODEC_ID_MSMPEG4V1,