hevc: Mark as having threadsafe init

Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

libavcodec/hevc.c

@@ -3416,5 +3416,6 @@ AVCodec ff_hevc_decoder = {
     .init_thread_copy      = hevc_init_thread_copy,
     .capabilities          = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY |
                              AV_CODEC_CAP_SLICE_THREADS | AV_CODEC_CAP_FRAME_THREADS,
+    .caps_internal         = FF_CODEC_CAP_INIT_THREADSAFE,
     .profiles              = NULL_IF_CONFIG_SMALL(ff_hevc_profiles),
 };