smb3: cleanup and clarify status of tree connections

smb3: cleanup and clarify status of tree connections

Currently the way the tid (tree connection) status is tracked
is confusing.  The same enum is used for structs cifs_tcon
and cifs_ses and TCP_Server_info, but each of these three has
different states that they transition among.  The current
code also unnecessarily uses camelCase.

Convert from use of statusEnum to a new tid_status_enum for
tree connections.  The valid states for a tid are:

        TID_NEW = 0,
        TID_GOOD,
        TID_EXITING,
        TID_NEED_RECON,
        TID_NEED_TCON,
        TID_IN_TCON,
        TID_NEED_FILES_INVALIDATE, /* unused, considering removing in future */
        TID_IN_FILES_INVALIDATE

It also removes CifsNeedTcon, CifsInTcon, CifsNeedFilesInvalidate and
CifsInFilesInvalidate from the statusEnum used for session and
TCP_Server_Info since they are not relevant for those.

A follow on patch will fix the places where we use the
tcon->need_reconnect flag to be more consistent with the tid->status.

Also fixes a bug that was:
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>