avcodec/cavsdec: Mark decoder as init-threadsafe

It does not initialize any static data in its .init.

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

libavcodec/cavsdec.c

@@ -1319,5 +1319,5 @@ const AVCodec ff_cavs_decoder = {
     .decode         = cavs_decode_frame,
     .capabilities   = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY,
     .flush          = cavs_flush,
-    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,
+    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
 };