[SCSI] libsas: use ->set_dmamode to notify lldds of NCQ parameters

sas_discover_sata() notifies lldds of sata devices twice.  Once to allow
the 'identify' to be sent, and a second time to allow aic94xx (the only
libsas driver that cares about sata_dev.identify) to setup NCQ
parameters before the device becomes known to the midlayer.  Replace
this double notification and intervening 'identify' with an explicit
->lldd_ata_set_dmamode notification.  With this change all ata internal
commands are issued by libata, so we no longer need sas_issue_ata_cmd().

The data from the identify command only needs to be cached in one
location so ata_device.id replaces domain_device.sata_dev.identify.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
index bd6e89e..9c13a5c0 100644
--- a/include/scsi/libsas.h
+++ b/include/scsi/libsas.h
@@ -164,9 +164,6 @@
 struct sata_device {
         enum   ata_command_set command_set;
         struct smp_resp        rps_resp; /* report_phy_sata_resp */
-        __le16 *identify_device;
-        __le16 *identify_packet_device;
-
         u8     port_no;        /* port number, if this is a PM (Port) */
         struct list_head children; /* PM Ports if this is a PM */
 
@@ -609,6 +606,7 @@
 	int (*lldd_clear_task_set)(struct domain_device *, u8 *lun);
 	int (*lldd_I_T_nexus_reset)(struct domain_device *);
 	int (*lldd_ata_soft_reset)(struct domain_device *);
+	void (*lldd_ata_set_dmamode)(struct domain_device *);
 	int (*lldd_lu_reset)(struct domain_device *, u8 *lun);
 	int (*lldd_query_task)(struct sas_task *);