Use $(ARCH) to allow using a different linker script for ppc64.
v2:
* Add ppc64/qemu/ldscript, derived from ppc/qemu/ldscript.
Signed-off-by: Andreas Färber <andreas.faerber@web.de>
git-svn-id: svn://coreboot.org/openbios/trunk/openbios-devel@929 f158a5a8-5612-0410-a976-696ce0be7e32