[libata] flags cleanup

Remove unused/redundant flags ATA_DFLAG_{MASTER,WCACHE}

drivers/scsi/ata_piix.c

@@ -390,7 +390,7 @@ static void piix_set_piomode (struct ata_port *ap, struct ata_device *adev)
 {
 	unsigned int pio	= adev->pio_mode;
 	struct pci_dev *dev	= ap->host_set->pdev;
-	unsigned int is_slave	= (adev->flags & ATA_DFLAG_MASTER) ? 0 : 1;
+	unsigned int is_slave	= (adev->devno != 0);
 	unsigned int master_port= ap->port_no ? 0x42 : 0x40;
 	unsigned int slave_port	= 0x44;
 	u16 master_data;

drivers/scsi/libata-core.c

@@ -2901,7 +2901,6 @@ static void ata_host_init(struct ata_port *ap, struct Scsi_Host *host,
 	ap->flags |= ent->host_flags;
 	ap->ops = ent->port_ops;
 	ap->cbl = ATA_CBL_NONE;
-	ap->device[0].flags = ATA_DFLAG_MASTER;
 	ap->active_tag = ATA_TAG_POISON;
 	ap->last_ctl = 0xFF;
 

include/linux/libata.h

@@ -87,10 +87,7 @@ enum {
 	/* struct ata_device stuff */
 	ATA_DFLAG_LBA48		= (1 << 0), /* device supports LBA48 */
 	ATA_DFLAG_PIO		= (1 << 1), /* device currently in PIO mode */
-	ATA_DFLAG_MASTER	= (1 << 2), /* is device 0? */
-	ATA_DFLAG_WCACHE	= (1 << 3), /* has write cache we can
-					     * (hopefully) flush? */
-	ATA_DFLAG_LOCK_SECTORS	= (1 << 4), /* don't adjust max_sectors */
+	ATA_DFLAG_LOCK_SECTORS	= (1 << 2), /* don't adjust max_sectors */
 
 	ATA_DEV_UNKNOWN		= 0,	/* unknown device */
 	ATA_DEV_ATA		= 1,	/* ATA device */