[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>

include/linux/libata.h

diff --git a/include/linux/libata.h b/include/linux/libata.h
index b6b8a7f..73b69c7 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -927,6 +927,8 @@
 extern int ata_scsi_detect(struct scsi_host_template *sht);
 extern int ata_scsi_ioctl(struct scsi_device *dev, int cmd, void __user *arg);
 extern int ata_scsi_queuecmd(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *));
+extern int ata_sas_scsi_ioctl(struct ata_port *ap, struct scsi_device *dev,
+			    int cmd, void __user *arg);
 extern void ata_sas_port_destroy(struct ata_port *);
 extern struct ata_port *ata_sas_port_alloc(struct ata_host *,
 					   struct ata_port_info *, struct Scsi_Host *);