Split the code for endian conversion into separate files for big and
little endian. The buildsystem selects the correct file for the used
endianness. Replace the swab macros with `static inline` c functions.
Define macros for returning the same or swapped value. Call those macros
in the endian specific files.
Change-Id: I86d38d816b37c283279c485fac8027f8fb94364a
Signed-off-by: Thomas Heijligen <thomas.heijligen@secunet.com>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/62898
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
