scsi: qedi: Fix TMF session block/unblock use

Drivers shouldn't be calling block/unblock session for tmf handling because
the functions can change the session state from under libiscsi.
iscsi_queuecommand's call to iscsi_prep_scsi_cmd_pdu->
iscsi_check_tmf_restrictions will prevent new cmds from being sent to qedi
after we've started handling a TMF. So we don't need to try and block it in
the driver, and we can remove these block calls.

Link: https://lore.kernel.org/r/20210525181821.7617-25-michael.christie@oracle.comReviewed-by: Manish Rangankar <mrangankar@marvell.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/qedi/qedi_fw.c

@@ -159,14 +159,9 @@ static void qedi_tmf_resp_work(struct work_struct *work)
 	set_bit(QEDI_CONN_FW_CLEANUP, &qedi_conn->flags);
 	resp_hdr_ptr =  (struct iscsi_tm_rsp *)qedi_cmd->tmf_resp_buf;
 
-	iscsi_block_session(session->cls_session);
 	rval = qedi_cleanup_all_io(qedi, qedi_conn, qedi_cmd->task, true);
-	if (rval) {
-		iscsi_unblock_session(session->cls_session);
+	if (rval)
 		goto exit_tmf_resp;
-	}
-
-	iscsi_unblock_session(session->cls_session);
 
 	spin_lock(&session->back_lock);
 	__iscsi_complete_pdu(conn, (struct iscsi_hdr *)resp_hdr_ptr, NULL, 0);