x86: clean up aperture_64.c

#include <asm/k8.h>

int gart_iommu_aperture;

int gart_iommu_aperture_disabled __initdata = 0;

int gart_iommu_aperture_allowed __initdata = 0;

int gart_iommu_aperture_disabled __initdata;

int gart_iommu_aperture_allowed __initdata;

int fallback_aper_order __initdata = 1; /* 64MB */

int fallback_aper_force __initdata = 0;

int fallback_aper_force __initdata;

int fix_aperture __initdata = 1;