lavfi/geq: mark timeline support

libavfilter/vf_geq.c

@@ -268,4 +268,5 @@ AVFilter avfilter_vf_geq = {
     .inputs        = geq_inputs,
     .outputs       = geq_outputs,
     .priv_class    = &geq_class,
+    .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
 };