[AGPGART] Make AGP depend on PCI

Fixes possible compile error in amd64 with pci=n
pointed out by Adrian Bunk.

Signed-off-by: Dave Jones <davej@redhat.com>
diff --git a/drivers/char/agp/Kconfig b/drivers/char/agp/Kconfig
index 7c88c06..3dbbb95 100644
--- a/drivers/char/agp/Kconfig
+++ b/drivers/char/agp/Kconfig
@@ -1,6 +1,7 @@
 config AGP
 	tristate "/dev/agpgart (AGP Support)" if !GART_IOMMU
 	depends on ALPHA || IA64 || PPC || X86
+	depends on PCI
 	default y if GART_IOMMU
 	---help---
 	  AGP (Accelerated Graphics Port) is a bus system mainly used to