cnic: Defer iscsi connection cleanup

The bnx2x devices require a 2 second quiet time before sending the last
RAMROD command to destroy a connection.  This sleep wait adds up to a
long delay when iscsid is serially destroying maultiple connections.

Create a workqueue to perform the final connection cleanup in the
background to speed up the process.  This significantly speeds up the
process as the wait time can be done in parallel for multiple connections.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/scsi/bnx2i/57xx_iscsi_constants.h b/drivers/scsi/bnx2i/57xx_iscsi_constants.h
index 2fceb19..1b6f86b 100644
--- a/drivers/scsi/bnx2i/57xx_iscsi_constants.h
+++ b/drivers/scsi/bnx2i/57xx_iscsi_constants.h
@@ -120,6 +120,8 @@
 /* additional LOM specific iSCSI license not installed */
 #define ISCSI_KCQE_COMPLETION_STATUS_LOM_ISCSI_NOT_ENABLED              (0x51)
 
+#define ISCSI_KCQE_COMPLETION_STATUS_CID_BUSY				(0x80)
+
 /* SQ/RQ/CQ DB structure sizes */
 #define ISCSI_SQ_DB_SIZE    (16)
 #define ISCSI_RQ_DB_SIZE    (16)