internal: Fix warnings about unused constants

By adding more #if guards, fix warnings about unused constants that
are enabled by default in newer GCC versions.

Change-Id: Ib3b6d7c0c2fadc4faeab971673bfadb1a6d25919
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/22669
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: David Hendricks <david.hendricks@gmail.com>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
(cherry picked from commit 97a90497a7d0df5076b4412c3e995a7e4a2ff8cc)
Reviewed-on: https://review.coreboot.org/22800
1 file changed