target-i386: Prepare CPUClass::class_by_name for X86CPU Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> Reviewed-by: Eduardo Habkost <ehabkost@redhat.com> Tested-by: Eduardo Habkost <ehabkost@redhat.com> Signed-off-by: Andreas Färber <afaerber@suse.de>