target/i386: Extract x86_cpu_exec_halt() from accel/tcg/

Move this x86-specific code out of the generic accel/tcg/.

Reported-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20240124101639.30056-10-philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
4 files changed