Create a a new configuration variable for PCI

Not all architectures have PCI. This new config variable allows control
of whether PCI support is configued in. It is selected for ARCH_X86.
Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>

Change-Id: Ic5fe777b14fd6a16ba605ada1e22acf3e8a2c783
Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>
Reviewed-on: http://review.coreboot.org/1947
Tested-by: build bot (Jenkins)
diff --git a/src/devices/Makefile.inc b/src/devices/Makefile.inc
index 9d4b391..9fe156b 100644
--- a/src/devices/Makefile.inc
+++ b/src/devices/Makefile.inc
@@ -2,14 +2,14 @@
 ramstage-y += root_device.c
 ramstage-y += cpu_device.c
 ramstage-y += device_util.c
-ramstage-y += pci_device.c
+ramstage-$(CONFIG_PCI) += pci_device.c
 ramstage-$(CONFIG_HYPERTRANSPORT_PLUGIN_SUPPORT) += hypertransport.c
 ramstage-$(CONFIG_PCIX_PLUGIN_SUPPORT) += pcix_device.c
-ramstage-y += pciexp_device.c
+ramstage-$(CONFIG_PCIEXP_PLUGIN_SUPPORT) += pciexp_device.c
 ramstage-$(CONFIG_AGP_PLUGIN_SUPPORT) += agp_device.c
 ramstage-$(CONFIG_CARDBUS_PLUGIN_SUPPORT) += cardbus_device.c
-ramstage-y += pnp_device.c
-ramstage-y += pci_ops.c
+ramstage-$(CONFIG_ARCH_X86) += pnp_device.c
+ramstage-$(CONFIG_PCI) += pci_ops.c
 ramstage-y += smbus_ops.c
 
 romstage-y+= device_romstage.c