ARM: dts: vexpress: Add CCI node to TC2 device-tree

The Versatile Express V2P-CA15_A7 (aka TC2) has a CCI-400 which is
needed to get Multi-Cluster Power Management (MCPM) working.

Signed-off-by: Jon Medhurst <tixy@linaro.org>
Acked-by: Pawel Moll <pawel.moll@arm.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Olof Johansson <olof@lixom.net>