zfcp: fix D_ID field with actual value on tracing SAN responses

With commit 2c55b750
("[SCSI] zfcp: Redesign of the debug tracing for SAN records.")
we lost the N_Port-ID where an ELS response comes from.
With commit 7c7dc196


("[SCSI] zfcp: Simplify handling of ct and els requests")
we lost the N_Port-ID where a CT response comes from.
It's especially useful if the request SAN trace record
with D_ID was already lost due to trace buffer wrap.

GS uses an open WKA port handle and ELS just a D_ID, and
only for ELS we could get D_ID from QTCB bottom via zfcp_fsf_req.
To cover both cases, add a new field to zfcp_fsf_ct_els
and fill it in on request to use in SAN response trace.
Strictly speaking the D_ID on SAN response is the FC frame's S_ID.
We don't need a field for the other end which is always us.

Signed-off-by: Steffen Maier <maier@linux.vnet.ibm.com>
Fixes: 2c55b750 ("[SCSI] zfcp: Redesign of the debug tracing for SAN records.")
Fixes: 7c7dc196

 ("[SCSI] zfcp: Simplify handling of ct and els requests")
Cc: <stable@vger.kernel.org> #2.6.38+
Reviewed-by: Benjamin Block <bblock@linux.vnet.ibm.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>