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)

src/Kconfig

@@ -203,6 +203,11 @@ source src/mainboard/Kconfig
 config ARCH_X86
 	bool
 	default n
+	select PCI
+
+config ARCH_ARM
+	bool
+	default n
 
 config ARCH_ARMV7
 	bool