[SCSI] libsas: kill sas_slave_destroy

Per commit 3e4ec344 "libata: kill ATA_FLAG_DISABLED" needing to set
ATA_DEV_NONE is a holdover from before libsas converted to the
"new-style" ata-eh.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

include/scsi/libsas.h

@@ -625,7 +625,6 @@ extern int sas_queuecommand(struct Scsi_Host * ,struct scsi_cmnd *);
 extern int sas_target_alloc(struct scsi_target *);
 extern int sas_slave_alloc(struct scsi_device *);
 extern int sas_slave_configure(struct scsi_device *);
-extern void sas_slave_destroy(struct scsi_device *);
 extern int sas_change_queue_depth(struct scsi_device *, int new_depth,
 				  int reason);
 extern int sas_change_queue_type(struct scsi_device *, int qt);