sconfig: add cpu device type

In order to enumerate CPU devices that are non-x86 (read: no lapic)
provide a generic 'cpu' device.

Change-Id: Ifeafdad8076935c3448784e6958117002509acbf
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/6824
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

util/sconfig/sconfig.y

@@ -30,7 +30,7 @@ static struct device *cur_parent, *cur_bus;
 	int number;
 }
 
-%token CHIP DEVICE REGISTER BOOL BUS RESOURCE END EQUALS HEX STRING PCI PNP I2C APIC CPU_CLUSTER DOMAIN IRQ DRQ IO NUMBER SUBSYSTEMID INHERIT IOAPIC_IRQ IOAPIC PCIINT
+%token CHIP DEVICE REGISTER BOOL BUS RESOURCE END EQUALS HEX STRING PCI PNP I2C APIC CPU_CLUSTER CPU DOMAIN IRQ DRQ IO NUMBER SUBSYSTEMID INHERIT IOAPIC_IRQ IOAPIC PCIINT
 %%
 devtree: { cur_parent = cur_bus = head; } chip { postprocess_devtree(); } ;