lavfi: support timeline for colorbalance and colorchannelmixer

Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavfilter/vf_colorbalance.c

@@ -209,4 +209,5 @@ AVFilter avfilter_vf_colorbalance = {
     .query_formats = query_formats,
     .inputs        = colorbalance_inputs,
     .outputs       = colorbalance_outputs,
+    .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE,
 };

libavfilter/vf_colorchannelmixer.c

@@ -367,4 +367,5 @@ AVFilter avfilter_vf_colorchannelmixer = {
     .query_formats = query_formats,
     .inputs        = colorchannelmixer_inputs,
     .outputs       = colorchannelmixer_outputs,
+    .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE,
 };