This should ideally be done once after all scene changes have been made.
Require an explicit call when everything is ready.
Always arrange after a key it sent, just for convenience.
Signed-off-by: Simon Glass <sjg@chromium.org>
Create an expo to handle the boot menu. For now this is quite simple, with
just a header, some menu items and a pointer to show the current one.
Signed-off-by: Simon Glass <sjg@chromium.org>
