x86 gart: rename CONFIG_IOMMU to CONFIG_GART_IOMMU

This patch renames the IOMMU config option to GART_IOMMU because in fact it
means the GART and not general support for an IOMMU on x86.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Acked-by: Muli Ben-Yehuda <muli@il.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/asm-x86/gart.h b/include/asm-x86/gart.h
index 5af471f..0765f3d 100644
--- a/include/asm-x86/gart.h
+++ b/include/asm-x86/gart.h
@@ -5,7 +5,7 @@
 extern void no_iommu_init(void);
 extern int force_iommu, no_iommu;
 extern int iommu_detected;
-#ifdef CONFIG_IOMMU
+#ifdef CONFIG_GART_IOMMU
 extern void gart_iommu_init(void);
 extern void gart_iommu_shutdown(void);
 extern void __init gart_parse_options(char *);