[SCSI] zfcp: fix device registration issues

The patch fixes following issues:

(1) Replace scsi_add_device with scsi_scan_target.
(Thus the rport instead of the scsi_host becomes parent of a
scsi_target again.)

(2) Avoid scsi_device allocation during registration of an remote port.
(Would be done during fc_scsi_scan_rport.)

(3) Fix queuecommand behaviour when an zfcp unit is blocked.
(Call scsi_done with DID_NO_CONNECT instead of returning
SCSI_MLQUEUE_DEVICE_BUSY otherwise we might end up waiting
for completion in blk_execute_rq for ever.)

Signed-off-by: Andreas Herrmann <aherrman@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/s390/scsi/zfcp_def.h b/drivers/s390/scsi/zfcp_def.h
index 7f551d6..6eba56c 100644
--- a/drivers/s390/scsi/zfcp_def.h
+++ b/drivers/s390/scsi/zfcp_def.h
@@ -664,6 +664,7 @@
 #define ZFCP_STATUS_UNIT_TEMPORARY		0x00000002
 #define ZFCP_STATUS_UNIT_SHARED			0x00000004
 #define ZFCP_STATUS_UNIT_READONLY		0x00000008
+#define ZFCP_STATUS_UNIT_REGISTERED		0x00000010
 
 /* FSF request status (this does not have a common part) */
 #define ZFCP_STATUS_FSFREQ_NOT_INIT		0x00000000