agp/amd64: Remove GART dependency on AGP_AMD64

The GART IOMMU code has no strong dependency to the AMD64
AGP code. So the automatic selection of AGP_AMD64 for GART
can be removed.

Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Pavel Vasilyev <pavel@pavlinux.ru>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

drivers/char/agp/Kconfig

@@ -56,9 +56,8 @@ config AGP_AMD
 	  X on AMD Irongate, 761, and 762 chipsets.
 
 config AGP_AMD64
-	tristate "AMD Opteron/Athlon64 on-CPU GART support" if !GART_IOMMU
+	tristate "AMD Opteron/Athlon64 on-CPU GART support"
 	depends on AGP && X86
-	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.