hw/arm/armsse: Add unimplemented-device stub for CPU local control registers

hw/arm/armsse: Add unimplemented-device stub for CPU local control registers

The SSE-200 has a "CPU local security control" register bank; add an
unimplemented-device stub for it. (The register bank has only one
interesting register, which allows the guest to lock down changes
to various CPU registers so they cannot be modified further. We
don't support that in our Cortex-M33 model anyway.)

Signed-off-by: Peter Maydell <[email protected]>
Reviewed-by: Richard Henderson <[email protected]>
Message-id: 20190121185118[email protected]