layout: Use linked list for `struct romentry`

This gets rid of the entry limit and hopefully makes future layout
handling easier. We start by making `struct flashrom_layout` private
to `layout.c`.

Change-Id: I60a0aa1007ebcd5eb401db116f835d129b3e9732
Signed-off-by: Nico Huber <nico.h@gmx.de>
Original-Reviewed-on: https://review.coreboot.org/c/flashrom/+/33521
Original-Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
Original-Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/72217
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
3 files changed