nyans: reduce code duplication in bootblock and romstages

this change reduces the code duplication of the bootblock and the romstages for
Nyans.

BUG=none
TEST=Built Nyan, Big, and Blaze. Ran faft on Blaze.
BRANCH=none
Original-Signed-off-by: dnojiri@chromium.org (Daisuke Nojiri)
Original-Change-Id: Ieb9dac3b061a2cf46c63afb2f31eb67ab391ea1a
Original-Reviewed-on: https://chromium-review.googlesource.com/214050
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>
Original-Commit-Queue: Daisuke Nojiri <dnojiri@chromium.org>
Original-Tested-by: Daisuke Nojiri <dnojiri@chromium.org>

(cherry picked from commit f3413d39458f03895fe4963a41285f71d81bcf5f)
Signed-off-by: Aaron Durbin <adurbin@chromium.org>

Change-Id: I912f63b12321aa26a7add302fc8a6c4e607330ef
Reviewed-on: http://review.coreboot.org/8880
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
16 files changed