Commit e79d5a6 ("machine: remove qemu_machine_opts global list") removed
the global option descriptions and moved them to MachineState's QOM
properties.

Query phandle-start by accessing machine properties through designated
wrappers.

Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>