meson: use `platform/` as subdir()

Move build instructions for files inside the `platform/` directory to
`platform/meson.build`. This contains instructions to build
`memaccess.c`, the right endian implementation and selecting the right
legacy command line option for the endian.

The `platform/` directory should contain code that abstracts the
underlying platform but is not involved in flashrom logic.

Change-Id: I88044a3f903f316138483dd872a6d95f8686ae69
Signed-off-by: Thomas Heijligen <thomas.heijligen@secunet.com>
Original-Reviewed-on: https://review.coreboot.org/c/flashrom/+/63826
Original-Reviewed-by: Anastasia Klimchuk <aklm@chromium.org>
Reviewed-on: https://review.coreboot.org/c/flashrom-stable/+/72332
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2 files changed