vf_split: define draw_slice() before end_frame()

Improve logical coherence, fix nit.

libavfilter/vf_split.c

@@ -33,6 +33,12 @@ static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *picref)
                          avfilter_ref_buffer(picref, ~AV_PERM_WRITE));
 }
 
+static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
+{
+    avfilter_draw_slice(inlink->dst->outputs[0], y, h, slice_dir);
+    avfilter_draw_slice(inlink->dst->outputs[1], y, h, slice_dir);
+}
+
 static void end_frame(AVFilterLink *inlink)
 {
     avfilter_end_frame(inlink->dst->outputs[0]);
@@ -41,12 +47,6 @@ static void end_frame(AVFilterLink *inlink)
     avfilter_unref_buffer(inlink->cur_buf);
 }
 
-static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
-{
-    avfilter_draw_slice(inlink->dst->outputs[0], y, h, slice_dir);
-    avfilter_draw_slice(inlink->dst->outputs[1], y, h, slice_dir);
-}
-
 AVFilter avfilter_vf_split = {
     .name      = "split",
     .description = NULL_IF_CONFIG_SMALL("Pass on the input to two outputs."),