ich_descriptors: Refactor read_ich_descriptors_from_dump()

Process the "upper map" early as it doesn't depend on the descriptor
generation. This way, we can use it to guess the generation.

Change-Id: Ia2786b762ccefdce31b63397119bd89879e887ff
Signed-off-by: Nico Huber <nico.h@gmx.de>
Original-Reviewed-on: https://review.coreboot.org/c/flashrom/+/55646
Original-Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/71386
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
1 file changed