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/drivers/char/agp/Kconfig b/drivers/char/agp/Kconfig
index f22c253..ccb1fa8 100644
--- a/drivers/char/agp/Kconfig
+++ b/drivers/char/agp/Kconfig
@@ -56,9 +56,9 @@
 	  X on AMD Irongate, 761, and 762 chipsets.
 
 config AGP_AMD64
-	tristate "AMD Opteron/Athlon64 on-CPU GART support" if !IOMMU
+	tristate "AMD Opteron/Athlon64 on-CPU GART support" if !GART_IOMMU
 	depends on AGP && X86
-	default y if IOMMU
+	default y if GART_IOMMU
 	help
 	  This option gives you AGP support for the GLX component of
 	  X using the on-CPU northbridge of the AMD Athlon64/Opteron CPUs.