internal: Fix #if guards for big-endian mips

Newer GCC still warns on big-endian mips, cf. 60210de
(internal: Fix warnings about unused constants).

Change-Id: Id0508c5241a7bd61b8d92d631cdf42ef7829a8a9
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/23003
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>
1 file changed