lavf/mkv: Ignore ff_isom_write_hvcc() return value as the mov muxer does.

This change allows remuxing hevc from mpeg-ts to Matroska.

libavformat/matroskaenc.c

@@ -605,8 +605,9 @@ static int mkv_write_native_codecprivate(AVFormatContext *s,
         return ff_isom_write_avcc(dyn_cp, codec->extradata,
                                   codec->extradata_size);
     case AV_CODEC_ID_HEVC:
-        return ff_isom_write_hvcc(dyn_cp, codec->extradata,
-                                  codec->extradata_size, 0);
+        ff_isom_write_hvcc(dyn_cp, codec->extradata,
+                           codec->extradata_size, 0);
+        return 0;
     case AV_CODEC_ID_ALAC:
         if (codec->extradata_size < 36) {
             av_log(s, AV_LOG_ERROR,