reform-boundary-uboot

After moving to KConfig and removing from all headers options should be
removed from config_whitelist.txt so the build starts complaining if
someone adds them back.

Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Chris Packham <judge.packham@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>