drivers/intel/fsp2_0: Add boot mode constants

This adds boot mode constants. They match EDK2 found in PiBootMode.h
constants but are part of FSP2.0 spec.

Change-Id: I16ee90ff372d252ddc042ca89c1e5912ab041616
Signed-off-by: Andrey Petrov <andrey.petrov@intel.com>
Reviewed-on: https://review.coreboot.org/14249
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins)
1 file changed