riff: Add a mapping for VP6A

This allows demuxing VP6A from F4V files.
Signed-off-by: Martin Storsjö <martin@martin.st>

libavformat/riff.c

@@ -228,6 +228,7 @@ const AVCodecTag ff_codec_bmp_tags[] = {
     { AV_CODEC_ID_VP6,          MKTAG('V', 'P', '6', '0') },
     { AV_CODEC_ID_VP6,          MKTAG('V', 'P', '6', '1') },
     { AV_CODEC_ID_VP6,          MKTAG('V', 'P', '6', '2') },
+    { AV_CODEC_ID_VP6A,         MKTAG('V', 'P', '6', 'A') },
     { AV_CODEC_ID_VP6F,         MKTAG('V', 'P', '6', 'F') },
     { AV_CODEC_ID_VP6F,         MKTAG('F', 'L', 'V', '4') },
     { AV_CODEC_ID_VP8,          MKTAG('V', 'P', '8', '0') },