nb/intel/nehalem: Don't link walkcbfs.S in romstage

Change-Id: I5bb0c38353d340cc5d356fba299a4460e3f5bddc
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35770
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/northbridge/intel/nehalem/Makefile.inc

@@ -26,7 +26,6 @@ romstage-y += memmap.c
 romstage-y += raminit.c
 romstage-y += raminit_tables.c
 romstage-y += early_init.c
-romstage-y += ../../../arch/x86/walkcbfs.S
 
 smm-y += finalize.c