nyan: Enable U-Boot as Legacy boot payload.

BUG=chrome-os-partner:24981
TEST=emerge-nyan* chromeos-bootimage # See U-Boot serial console in Cltr-L
CQ-DEPEND=CL:199504

Change-Id: I9d15fb02f15b3f93652fbf5cdc21ccc7477b064c
Reviewed-on: https://chromium-review.googlesource.com/200224
Tested-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: David Hendricks <dhendrix@chromium.org>
Commit-Queue: Hung-Te Lin <hungte@chromium.org>
1 file changed