cxgbit: Use type ISCSI_CXGBIT + cxgbit tpg_np attribute

Instead of having cxgbit use type ISCSI_HW_OFFLOAD + 'hw_offload'
tpg_np attribute, it should be using it's own driver specific
type + attribute

Cc: Varun Prakash <varun@chelsio.com>
Cc: Hariprasad Shenai <hariprasad@chelsio.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/iscsi/cxgbit/cxgbit_main.c

@@ -624,7 +624,7 @@ static enum target_prot_op cxgbit_get_sup_prot_ops(struct iscsi_conn *conn)
 
 static struct iscsit_transport cxgbit_transport = {
 	.name			= DRV_NAME,
-	.transport_type		= ISCSI_HW_OFFLOAD,
+	.transport_type		= ISCSI_CXGBIT,
 	.rdma_shutdown		= false,
 	.priv_size		= sizeof(struct cxgbit_cmd),
 	.owner			= THIS_MODULE,