toytoolkit: Remove window_damage()

It's just a direct call to wl_surface_damage() anyway, and the only
caller no longer exists.

Signed-off-by: Derek Foreman <derekf@osg.samsung.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>

clients/window.c

@@ -4473,13 +4473,6 @@ window_set_text_cursor_position(struct window *window, int32_t x, int32_t y)
 				    wl_fixed_from_int(y));
 }
 
-void
-window_damage(struct window *window, int32_t x, int32_t y,
-	      int32_t width, int32_t height)
-{
-	wl_surface_damage(window->main_surface->surface, x, y, width, height);
-}
-
 static void
 surface_enter(void *data,
 	      struct wl_surface *wl_surface, struct wl_output *wl_output)

clients/window.h

@@ -343,10 +343,6 @@ window_schedule_redraw(struct window *window);
 void
 window_schedule_resize(struct window *window, int width, int height);
 
-void
-window_damage(struct window *window, int32_t x, int32_t y,
-	      int32_t width, int32_t height);
-
 cairo_surface_t *
 window_get_surface(struct window *window);