window.c: Don't allow moving a maximized window

Ideally the shell would send an unmaximize event to the client when
we try to move a maximized window, but for now, let's just prevent
moving maximized windows.

https://bugs.freedesktop.org/show_bug.cgi?id=56296

clients/window.c

@@ -2083,6 +2083,9 @@ frame_get_pointer_image_for_location(struct frame *frame, struct input *input)
 	struct window *window = frame->widget->window;
 	int location;
 
+	if (window->type != TYPE_TOPLEVEL)
+		return CURSOR_LEFT_PTR;
+
 	location = theme_get_location(t, input->sx, input->sy,
 				      frame->widget->allocation.width,
 				      frame->widget->allocation.height,
@@ -2200,6 +2203,9 @@ frame_button_handler(struct widget *widget,
 	struct display *display = window->display;
 	int location;
 
+	if (window->type != TYPE_TOPLEVEL)
+		return;
+
 	location = theme_get_location(display->theme, input->sx, input->sy,
 				      frame->widget->allocation.width,
 				      frame->widget->allocation.height,