layout: Get rid of struct typedef and use upstream name

Start to converge our local implementation with upstreams that
was worked on around the `commit 3a9939b952e` as a point of reference.

BUG=chromium:478356
BRANCH=none
TEST=still builds

Change-Id: Id42e697e16d9d4ded82eeb2777c84719d2d9a636
Signed-off-by: Edward O'Callaghan <quasisec@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/flashrom/+/1672913
Reviewed-by: Sam McNally <sammc@chromium.org>
5 files changed