[coreboot] Makefile simplification for v3

[Myles Watson]

> >
> > I've attached the original two patches minus the QEMU part.  Which one
> > do people like better?
> >
> > Myles
> >
> > Signed-off-by: Myles Watson <mylesgw at gmail.com>
> >
> 
> simplify.patch is better because it keeps LARFILES_* free of $(obj)
> stuff which doesn't belong there.
> Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006 at gmx.net>

Rev 639.

Thanks,
Myles