hw/misc/armsse-cpuid: Implement SSE-200 CPU_IDENTITY register block

hw/misc/armsse-cpuid: Implement SSE-200 CPU_IDENTITY register block

The SSE-200 has a CPU_IDENTITY register block, which is a set of
read-only registers. As well as the usual PID/CID registers, there
is a single CPUID register which indicates whether the CPU is CPU 0
or CPU 1. Implement a model of this register block.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20190121185118.18550-20-peter.maydell@linaro.org