splitter: create display with correct window size

So far, the display was created without a requested size. Then its size
was immediately changed to that of the window.

With this change, the display is created directly with the correct size.
This matches the core video output behaviour.

modules/video_output/splitter.c

@@ -300,9 +300,14 @@ static int vlc_vidsplit_Open(vout_display_t *vd,
         }
 
         vdcfg.window = part->window;
+        vlc_sem_wait(&part->lock);
+        vdcfg.window_props.width = part->width;
+        vdcfg.window_props.height = part->height;
+
         vout_display_t *display = vout_display_New(obj, &output->fmt, ctx, &vdcfg,
                                                    modname, NULL);
         if (display == NULL) {
+            vlc_sem_post(&part->lock);
             vout_window_Disable(part->window);
             vout_window_Delete(part->window);
             splitter->i_output = i;
@@ -310,9 +315,7 @@ static int vlc_vidsplit_Open(vout_display_t *vd,
             return VLC_EGENERIC;
         }
 
-        vlc_sem_wait(&part->lock);
         part->display = display;
-        vout_display_SetSize(display, part->width, part->height);
         vlc_sem_post(&part->lock);
     }