Since the only user of the extended cpu_list_id() format
was the x86 ?model/?dump/?cpuid output, we can drop it
completely.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>