ARM: dts: arm_cci: add hw-version property

Add the hw-version property to the cci-400 Cache Coherent
Interconnect. This is used when the hardware version number
cannot be read by a non-secure read. The version number is
only needed to distinguish older legacy versions of the module.

Change-Id: I47d25028a3720643a694829014a7b042dc73c9ac
Signed-off-by: Neil Leeder <nleeder@codeaurora.org>