pc: Don't use QEMUMachine anymore Now that we have a DEFINE_PC_MACHINE helper macro that just requires an initialization function, it is trivial to convert them to register a QOM machine class directly, instead of using QEMUMachine. Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>