memory: drop needless argument

The argument is unused since commit bdc44640 ("cpu: Use QTAILQ for CPU list").

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20231009075231.150568-1-marcandre.lureau@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>