lavc/libdavs2: enable multithread

Reviewed-by: Steven Liu <lq@chinaffmpeg.org>
Signed-off-by: hwrenx <hwrenx@126.com>

libavcodec/libdavs2.c

@@ -205,7 +205,7 @@ AVCodec ff_libdavs2_decoder = {
     .init           = davs2_init,
     .close          = davs2_end,
     .decode         = davs2_decode_frame,
-    .capabilities   =  AV_CODEC_CAP_DELAY,//AV_CODEC_CAP_DR1 |
+    .capabilities   =  AV_CODEC_CAP_DELAY | AV_CODEC_CAP_AUTO_THREADS,
     .pix_fmts       = (const enum AVPixelFormat[]) { AV_PIX_FMT_YUV420P,
                                                      AV_PIX_FMT_NONE },
     .wrapper_name   = "libdavs2",