x86: clean up iommu.h and gart.h

This remove lots of duplications in iommu.h and gart.h.

The end result of this patch is:

- iommu.h is a header file for everyone related with IOMMUs.

- gart.h is the private header file. Only pci-gart_64.c and its friends
  include it.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: fujita.tomonori@lab.ntt.co.jp
Signed-off-by: NIngo Molnar <mingo@elte.hu>

include/asm-x86/gart.h

-#ifndef _ASM_X8664_IOMMU_H
-#define _ASM_X8664_IOMMU_H 1
+#ifndef _ASM_X8664_GART_H
+#define _ASM_X8664_GART_H 1
 
 #include <asm/e820.h>
+#include <asm/iommu.h>
 
-extern void pci_iommu_shutdown(void);
-extern void no_iommu_init(void);
-extern int force_iommu, no_iommu;
-extern int iommu_detected;
-extern int agp_amd64_init(void);
-#ifdef CONFIG_GART_IOMMU
-extern void gart_iommu_init(void);
-extern void gart_iommu_shutdown(void);
-extern void __init gart_parse_options(char *);
-extern void early_gart_iommu_check(void);
-extern void gart_iommu_hole_init(void);
 extern void set_up_gart_resume(u32, u32);
+
 extern int fallback_aper_order;
 extern int fallback_aper_force;
-extern int gart_iommu_aperture;
-extern int gart_iommu_aperture_allowed;
-extern int gart_iommu_aperture_disabled;
 extern int fix_aperture;
-#else
-#define gart_iommu_aperture		0
-#define gart_iommu_aperture_allowed	0
-#define gart_iommu_aperture_disabled	1
-
-static inline void early_gart_iommu_check(void)
-{
-}
-
-static inline void gart_iommu_shutdown(void)
-{
-}
-
-#endif
 
 /* PTE bits. */
 #define GPTE_VALID	1

include/asm-x86/iommu.h

-#ifndef _ASM_X8664_GART_H
-#define _ASM_X8664_GART_H 1
+#ifndef _ASM_X8664_IOMMU_H
+#define _ASM_X8664_IOMMU_H 1
 
 extern void pci_iommu_shutdown(void);
 extern void no_iommu_init(void);
 extern int force_iommu, no_iommu;
 extern int iommu_detected;
+
 #ifdef CONFIG_GART_IOMMU
+extern int gart_iommu_aperture;
+extern int gart_iommu_aperture_allowed;
+extern int gart_iommu_aperture_disabled;
+
+extern void early_gart_iommu_check(void);
 extern void gart_iommu_init(void);
 extern void gart_iommu_shutdown(void);
 extern void __init gart_parse_options(char *);
-extern void iommu_hole_init(void);
-extern int fallback_aper_order;
-extern int fallback_aper_force;
-extern int iommu_aperture;
-extern int iommu_aperture_allowed;
-extern int iommu_aperture_disabled;
-extern int fix_aperture;
+extern void gart_iommu_hole_init(void);
+
 #else
-#define iommu_aperture 0
-#define iommu_aperture_allowed 0
+#define gart_iommu_aperture            0
+#define gart_iommu_aperture_allowed    0
+#define gart_iommu_aperture_disabled   1
 
-static inline void gart_iommu_shutdown(void)
+static inline void early_gart_iommu_check(void)
 {
 }
 
+static inline void gart_iommu_shutdown(void)
+{
+}
 #endif
 
 #endif