avcodec: add Mandsoft Screen Capture Codec decoder

Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavformat/riff.c

@@ -452,6 +452,7 @@ const AVCodecTag ff_codec_bmp_tags[] = {
     { AV_CODEC_ID_SCPR,         MKTAG('S', 'C', 'P', 'R') },
     { AV_CODEC_ID_CLEARVIDEO,   MKTAG('U', 'C', 'O', 'D') },
     { AV_CODEC_ID_AV1,          MKTAG('A', 'V', '0', '1') },
+    { AV_CODEC_ID_MSCC,         MKTAG('M', 'S', 'C', 'C') },
     { AV_CODEC_ID_NONE,         0 }
 };