[PATCH 17/20] lightnvm: define chunk states

Define chunk states as given in the 2.0 spec. Also, add an extra chunk state that signals that the chunk is in use by the host. This allows for the chunk metadata to be "owned" by a target when active, thus completing the chunk state machine from the host perspective and facilitating sanity

[PATCH 17/20] lightnvm: define chunk states

Define chunk states as given in the 2.0 spec. Also, add an extra chunk state that signals that the chunk is in use by the host. This allows for the chunk metadata to be "owned" by a target when active, thus completing the chunk state machine from the host perspective and facilitating sanity