avcodec/idcinvideo: Mark decoder as init-threadsafe

Reviewed-by: Tomas Härdin <tjoppen@acc.umu.se>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

libavcodec/idcinvideo.c

@@ -258,4 +258,5 @@ AVCodec ff_idcin_decoder = {
     .decode         = idcin_decode_frame,
     .capabilities   = AV_CODEC_CAP_DR1,
     .defaults       = idcin_defaults,
+    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
 };