[U-Boot] [RFC] Menu Frameworj

[Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>]

Hi,

	The following patch will introduce a menu framework
	that allow us to create list menu to simplify u-boot and make it more
	convivial for the end-user.

	This kind of menu is very usefull when you do not have a keyboard or a
	serial console attached to your board to allow you to interract with
	u-boot

	For the develloper part,
	The framework introduce two API

	1) C
	that allow you to create menu, submenu, entry and complex menu action

	2) Command
	that allow you as the C API to create menu, submenu, entry and complex
	menu action but this time the actions will be store in a env var and
	then be evaluated and excecuted.

	NB the current code need somework to be mainline as doc, error message
	but it's functionnal. So feel free to test and improve

Best Regards,
J.