rtpdec: Use AVERROR_PATCHWELCOME instead of AVERROR(ENOSYS) for

unimplemented features
Signed-off-by: Martin Storsjö <martin@martin.st>

libavformat/rtpdec_h264.c

@@ -354,7 +354,7 @@ static int h264_handle_packet(AVFormatContext *ctx, PayloadContext *data,
         av_log(ctx, AV_LOG_ERROR,
                "Unhandled type (%d) (See RFC for implementation details)\n",
                type);
-        result = AVERROR(ENOSYS);
+        result = AVERROR_PATCHWELCOME;
         break;
 
     case 28:                   // FU-A (fragmented nal)

libavformat/rtpdec_vp9.c

@@ -223,7 +223,7 @@ static int vp9_handle_packet(AVFormatContext *ctx, PayloadContext *rtp_vp9_ctx,
      */
     if (has_ss_data) {
         avpriv_report_missing_feature(ctx, "VP9 scalability structure data");
-        return AVERROR(ENOSYS);
+        return AVERROR_PATCHWELCOME;
     }
 
     /*