cpus: Restrict 'start-powered-off' property to system emulation

Since the CPUState::start-powered-off property is irrelevant
to user emulation, restrict it to system emulation.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20240111161817.43150-1-philmd@linaro.org>
1 file changed