eficonfig: refactor change boot order implementation

eficonfig: refactor change boot order implementation

This commit removes the change boot order specific
menu implementation. The change boot order implementation
calls eficonfig_process_common() same as other menus.

The change boot order menu requires own item_data_print
and item_choice implementation, but display_statusline
function can be a same function as other menus.

Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>