scsi: target: add device vendor id, product id and revision configfs attributes

scsi: target: add device vendor id, product id and revision configfs attributes

The vendor_id, product_id and revision attributes will allow for the
modification of the T10 Model and Revision strings returned in
inquiry responses. Its value can be viewed and modified via the
ConfigFS path at:

target/core/$backstore/$name/wwn/vendor_id
target/core/$backstore/$name/wwn/product_id
target/core/$backstore/$name/wwn/revision

Orabug: 29344862

Signed-off-by: Alan Adamson <alan.adamson@oracle.com>
Reviewed-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Brian Maly <brian.maly@oracle.com>