zfcp: Revert to original scanning behaviour

zfcp has its own mechanism for selective scanning, so revert to the
original scanning behaviour to not confuse users.

Fixes: 4e91e876e9b8b6eb4255aa0d690778a89d3f1d28
Suggested-by: Benjamin Block <bblock@linux.vnet.ibm.com>
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Benjamin Block <bblock@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>