x86: broadwell: Allow booting from SPL

At present broadwell only supports booting straight into U-Boot proper.
Add a separate init file to boot from SPL into U-Boot proper, and select
it when SPL is in use.

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