libata: implement and use SHT initializers

libata lets low level drivers build scsi_host_template and register it
to the SCSI layer.  This allows low level drivers high level of
flexibility but also burdens them with lots of boilerplate entries.

This patch implements SHT initializers which can be used to initialize
all the boilerplate entries in a sht.  Three variants of them are
implemented - BASE, BMDMA and NCQ - for different types of drivers.
Note that entries can be overriden by putting individual initializers
after the helper macro.

All sht tables are identical before and after this patch.

Signed-off-by: Tejun Heo <htejun@gmail.com>

drivers/ata/pata_at32.c

@@ -167,21 +167,7 @@ static void pata_at32_set_piomode(struct ata_port *ap, struct ata_device *adev)
 }
 
 static struct scsi_host_template at32_sht = {
-	.module			= THIS_MODULE,
-	.name			= DRV_NAME,
-	.ioctl			= ata_scsi_ioctl,
-	.queuecommand		= ata_scsi_queuecmd,
-	.can_queue		= ATA_DEF_QUEUE,
-	.this_id		= ATA_SHT_THIS_ID,
-	.sg_tablesize		= LIBATA_MAX_PRD,
-	.cmd_per_lun		= ATA_SHT_CMD_PER_LUN,
-	.emulated		= ATA_SHT_EMULATED,
-	.use_clustering		= ATA_SHT_USE_CLUSTERING,
-	.proc_name		= DRV_NAME,
-	.dma_boundary		= ATA_DMA_BOUNDARY,
-	.slave_configure	= ata_scsi_slave_config,
-	.slave_destroy		= ata_scsi_slave_destroy,
-	.bios_param		= ata_std_bios_param,
+	ATA_PIO_SHT(DRV_NAME),
 };
 
 static struct ata_port_operations at32_port_ops = {