[SCSI] bnx2i: Task management ABORT TASK fixes

Due to typo error driver was failing TMF Abort Task request when
ctask->sc != NULL. Fixed code to fail TMF ABORT Task request only when
ctask->sc == NULL.  Clear age component (19 most significant bits) of
reference ITT carried in iSCSI TMF PDU. Age component is internal to
initiator side and only lower bits of ITT as defined by ISCSI_ITT_MASK
is is sent on wire.  Retrieve LUN directly from the ref_sc and update
SQ wqe as per chip HSI (Host Software Interface) specification

Signed-off-by: Anil Veerabhadrappa <anilgv@broadcom.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>