vc2enc: mark as FF_CODEC_CAP_INIT_THREADSAFE and align AVCodec entries

The encoder does not modify any global variables.
Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>

libavcodec/vc2enc.c

@@ -1193,6 +1193,7 @@ AVCodec ff_vc2_encoder = {
     .init           = vc2_encode_init,
     .close          = vc2_encode_end,
     .capabilities   = AV_CODEC_CAP_SLICE_THREADS,
+    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
     .encode2        = vc2_encode_frame,
     .priv_class     = &vc2enc_class,
     .defaults       = vc2enc_defaults,