avfilter/avfiltergraph: dont "or" together error codes

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavfilter/avfiltergraph.c

@@ -564,19 +564,19 @@ static int query_formats(AVFilterGraph *graph, AVClass *log_ctx)
                 outlink = convert->outputs[0];
                 if (!ff_merge_formats( inlink->in_formats,  inlink->out_formats,  inlink->type) ||
                     !ff_merge_formats(outlink->in_formats, outlink->out_formats, outlink->type))
-                    ret |= AVERROR(ENOSYS);
+                    ret = AVERROR(ENOSYS);
                 if (inlink->type == AVMEDIA_TYPE_AUDIO &&
                     (!ff_merge_samplerates(inlink->in_samplerates,
                                            inlink->out_samplerates) ||
                      !ff_merge_channel_layouts(inlink->in_channel_layouts,
                                                inlink->out_channel_layouts)))
-                    ret |= AVERROR(ENOSYS);
+                    ret = AVERROR(ENOSYS);
                 if (outlink->type == AVMEDIA_TYPE_AUDIO &&
                     (!ff_merge_samplerates(outlink->in_samplerates,
                                            outlink->out_samplerates) ||
                      !ff_merge_channel_layouts(outlink->in_channel_layouts,
                                                outlink->out_channel_layouts)))
-                    ret |= AVERROR(ENOSYS);
+                    ret = AVERROR(ENOSYS);
 
                 if (ret < 0) {
                     av_log(log_ctx, AV_LOG_ERROR,