avcodec/jvdec: Mark decoder as init-threadsafe

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

libavcodec/jvdec.c

@@ -243,4 +243,5 @@ const AVCodec ff_jv_decoder = {
     .close          = decode_close,
     .decode         = decode_frame,
     .capabilities   = AV_CODEC_CAP_DR1,
+    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
 };