loopback: Add fabric_prot_type attribute support

This patch updates loopback to add a new fabric_prot_type TPG attribute,
used for controlling LLD level protection into LIO when the backend
device does not support T10-PI.

Also, go ahead and set DIN_PASS + DOUT_PASS so target-core knows that
it will be doing any WRITE_STRIP and READ_INSERT operations.

Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/loopback/tcm_loop.h

@@ -43,6 +43,7 @@ struct tcm_loop_nacl {
 struct tcm_loop_tpg {
 	unsigned short tl_tpgt;
 	unsigned short tl_transport_status;
+	enum target_prot_type tl_fabric_prot_type;
 	atomic_t tl_tpg_port_count;
 	struct se_portal_group tl_se_tpg;
 	struct tcm_loop_hba *tl_hba;