xwm: Fix input region regression from commit changes

This must be the last regression from the surface commit changes.  We
need to set the pending.input region, otherwise the region will be
overwritten on commit.

https://bugs.freedesktop.org/show_bug.cgi?id=60610

src/xwayland/window-manager.c

@@ -828,8 +828,10 @@ weston_wm_window_draw_decoration(void *data)
 					       window->width + 2,
 					       window->height + 2);
 		window->surface->geometry.dirty = 1;
+	}
 
-		pixman_region32_init_rect(&window->surface->input,
+	if (window->surface && !window->fullscreen) {
+		pixman_region32_init_rect(&window->surface->pending.input,
 					  t->margin, t->margin,
 					  width - 2 * t->margin,
 					  height - 2 * t->margin);