uboot-phytec

x86: Support SPL and TPL

At present only chromebook_link64 supports SPL. It is useful to eb able to
support both TPL and SPL to implement verified boot on x86.

Enable the options for both along with some suitable default options
needed to boot through these phases.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>