vaapi_h264: Do not use deprecated header type

SEI headers should be inserted as generic raw data (the old specific
type has been deprecated in libva2).

libavcodec/vaapi_encode_h264.c

@@ -256,7 +256,7 @@ static int vaapi_encode_h264_write_extra_header(AVCodecContext *avctx,
 
         ff_cbs_fragment_uninit(priv->cbc, au);
 
-        *type = VAEncPackedHeaderH264_SEI;
+        *type = VAEncPackedHeaderRawData;
         return 0;
     } else {
         return AVERROR_EOF;