[libata] get-identity ioctl: Fix use of invalid memory pointer

for SAS drivers.

Caught by Ke Wei (and team?) at Marvell.

Also, move the ata_scsi_ioctl export to libata-scsi.c, as that seems to be the
general trend.

Acked-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/scsi/libsas/sas_scsi_host.c

@@ -717,7 +717,7 @@ int sas_ioctl(struct scsi_device *sdev, int cmd, void __user *arg)
 	struct domain_device *dev = sdev_to_domain_dev(sdev);
 
 	if (dev_is_sata(dev))
-		return ata_scsi_ioctl(sdev, cmd, arg);
+		return ata_sas_scsi_ioctl(dev->sata_dev.ap, sdev, cmd, arg);
 
 	return -EINVAL;
 }