Since commit e67db06e9f (target-or32: Add
target stubs and QOM cpu) a VMStateDescription existed, but
CPU_SAVE_VERSION was not set, so it was never registered.
Drop cpu_{save,load}() and register VMStateDescription via DeviceState.
Use a version_id of 1 and specify minimum versions as well.
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>