layout.c: Don't use global variables for included regions

This removes the use of global variables for included region arguments
and also uses a linked list to store the arguments.

Change-Id: I6534cc58b8dcc6256c2730c809286d8083669a6c
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/31247
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
4 files changed