ocp/deltalake: Set C-State config

Set the supported C-State to C1 and C6. This matches the states in
CPUID(5).

Change-Id: If32b8256097b5b2bee7fb074fab105e4b54d14b3
Signed-off-by: Marc Jones <marcjones@sysproconsulting.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/49803
Reviewed-by: Jonathan Zhang <jonzhang@fb.com>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/ocp/deltalake/devicetree.cb

@@ -46,6 +46,8 @@ chip soc/intel/xeon_sp/cpx
 		.PortLinkSpeed = PcieAuto,
 	}"
 
+	register "cstate_states" = "CSTATES_C1C6"
+
 	device cpu_cluster 0 on
 	  device lapic 0 on end
 	end