x86: GART: Convert gart_iommu_hole_init() to use iommu_init hook

This changes gart_iommu_hole_init() to set gart_iommu_init() to
iommu_init hook if gart_iommu_hole_init() finds the GART IOMMU.

We can kill the code to check if we found the IOMMU in
gart_iommu_init() since gart_iommu_hole_init() sets
gart_iommu_init() only when it found the IOMMU.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: chrisw@sous-sol.org
Cc: dwmw2@infradead.org
Cc: joerg.roedel@amd.com
Cc: muli@il.ibm.com
LKML-Reference: <1257849980-22640-4-git-send-email-fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/include/asm/gart.h b/arch/x86/include/asm/gart.h
index 4fdd5b3..4ac5b0f 100644
--- a/arch/x86/include/asm/gart.h
+++ b/arch/x86/include/asm/gart.h
@@ -35,7 +35,7 @@
 extern int gart_iommu_aperture_disabled;
 
 extern void early_gart_iommu_check(void);
-extern void gart_iommu_init(void);
+extern int gart_iommu_init(void);
 extern void __init gart_parse_options(char *);
 extern void gart_iommu_hole_init(void);
 
@@ -47,9 +47,6 @@
 static inline void early_gart_iommu_check(void)
 {
 }
-static inline void gart_iommu_init(void)
-{
-}
 static inline void gart_parse_options(char *options)
 {
 }