cpus: Keep default fields initialization in cpu_common_initfn()

cpus: Keep default fields initialization in cpu_common_initfn()

cpu_common_initfn() is our target agnostic initializer,
while cpu_exec_initfn() is the target specific one.

The %as and %num_ases fields are not target specific,
so initialize them in the common helper.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20250123234415.59850-6-philmd@linaro.org>