[SCSI] libiscsi, iscsi_tcp, ib_iser : add sw iscsi host get/set params helpers

iscsid and udev need to key off the hw address being
used so add some helpers for iser and iscsi tcp.

Also convert them

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Cc: Roland Dreier <rdreier@cisco.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>