qla2xxx: Track I-T nexus as single fc_port struct

Current code merges qla_tgt_sess and fc_port structure
into single fc_port structure representing same I-T nexus.

Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
[ bvanassche: fixed spelling of patch description ]
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>