[SCSI] iscsi: convert xmit path to iscsi chunks

Convert xmit to iscsi chunks.

from michaelc@cs.wisc.edu:

Bug fixes, more digest integration, sg chaining conversion and other
sg wrapper changes, coding style sync up, and removal of io fields,
like pdu_sent, that are not needed.

Signed-off-by: Olaf Kirch <olaf.kirch@oracle.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/infiniband/ulp/iser/iscsi_iser.c

@@ -129,7 +129,7 @@ iscsi_iser_recv(struct iscsi_conn *conn,
  * iscsi_iser_cmd_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
  *
  **/
-static void
+static int
 iscsi_iser_cmd_init(struct iscsi_cmd_task *ctask)
 {
 	struct iscsi_iser_conn     *iser_conn  = ctask->conn->dd_data;
@@ -138,6 +138,7 @@ iscsi_iser_cmd_init(struct iscsi_cmd_task *ctask)
 	iser_ctask->command_sent = 0;
 	iser_ctask->iser_conn    = iser_conn;
 	iser_ctask_rdma_init(iser_ctask);
+	return 0;
 }
 
 /**