[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>
diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index 841f460..0782900 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -4912,7 +4912,7 @@
 	if (res && ipr_is_gata(res)) {
 		if (cmd == HDIO_GET_IDENTITY)
 			return -ENOTTY;
-		return ata_scsi_ioctl(sdev, cmd, arg);
+		return ata_sas_scsi_ioctl(res->sata_port->ap, sdev, cmd, arg);
 	}
 
 	return -EINVAL;