avcodec/pcm-dvd: Mark decoder as init-threadsafe

Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

libavcodec/pcm-dvd.c

@@ -303,5 +303,6 @@ AVCodec ff_pcm_dvd_decoder = {
                       AV_CODEC_CAP_DR1,
     .sample_fmts    = (const enum AVSampleFormat[]) {
         AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_NONE
-    }
+    },
+    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
 };