ceph-volume: show correct rejected reason in inventory if device type is not acceptable

ceph-volume: show correct rejected reason in inventory if device type is not acceptable

If device type is not acceptable in `c-v inventory`, its rejected reason
becomes "Insufficient space (<5GB)" by mistake. It's because sys_api is
empty due to skipping devices that are neither `disk` nor `device`. We
should report the target device is not acceptable in this case.

Fixes: https://tracker.ceph.com/issues/46102
Signed-off-by: Satoru Takeuchi <satoru.takeuchi@gmail.com>