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/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 970b2de..fbd77b7 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -91,7 +91,7 @@
 
 config IOMMU_DEBUG
 	bool "Enable IOMMU debugging"
-	depends on IOMMU && DEBUG_KERNEL
+	depends on GART_IOMMU && DEBUG_KERNEL
 	depends on X86_64
 	help
 	  Force the IOMMU to on even when you have less than 4GB of