[PATCH] libata: clear ATA_DFLAG_PIO before setting it

ata_dev_set_mode() is now responsible for managing ATA_DFLAG_PIO.
Clear it before setting it.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

drivers/scsi/libata-core.c

@@ -1949,6 +1949,7 @@ static int ata_dev_set_mode(struct ata_port *ap, struct ata_device *dev)
 	unsigned int err_mask;
 	int rc;
 
+	dev->flags &= ~ATA_DFLAG_PIO;
 	if (dev->xfer_shift == ATA_SHIFT_PIO)
 		dev->flags |= ATA_DFLAG_PIO;