This builds and displays an SPL message, but does not function beyond that.

Signed-off-by: Simon Glass <sjg@chromium.org>

On x86 it is common to use 'post codes' which are 8-bit hex values emitted
from the code and visible to the user. Traditionally two 7-segment displays
were made available on the motherboard to show the last post code that was
emitted. This allows diagnosis of a boot problem since it is possible to
see where the code got to before it died.

On modern hardware these codes are not normally visible. On Chromebooks
they are displayed by the Embedded Controller (EC), so it is useful to emit
them. We must enable this feature for the EC to see the codes, so add an
option for this.

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

This board is a 'bare' version of the existing 'link 'board. It does not
require coreboot to run, but is intended to start directly from the reset
vector.

This initial commit has place holders for a wide range of features. These
will be added in follow-on patches and series. So far it cannot be booted
as there is no ROM image produced, but it does build without errors.

Signed-off-by: Simon Glass <sjg@chromium.org>