[SCSI] SPI transport class, don't negotiate options not supported

At the moment, the transport class blindly tries to set things like
QAS and IU, even if the drive won't support them.  It's best not to
annoy the devices like this and instead only set what the drive says
is actually supported.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/scsi_transport_spi.c b/drivers/scsi/scsi_transport_spi.c
index 2918b96..7670919 100644
--- a/drivers/scsi/scsi_transport_spi.c
+++ b/drivers/scsi/scsi_transport_spi.c
@@ -795,7 +795,8 @@
 	}
 
 	/* test width */
-	if (i->f->set_width && spi_max_width(starget) && sdev->wdtr) {
+	if (i->f->set_width && spi_max_width(starget) &&
+	    scsi_device_wide(sdev)) {
 		i->f->set_width(starget, 1);
 
 		if (spi_dv_device_compare_inquiry(sreq, buffer,
@@ -811,14 +812,14 @@
 		return;
 
 	/* device can't handle synchronous */
-	if (!sdev->ppr && !sdev->sdtr)
+	if (!scsi_device_sync(sdev) && !scsi_device_dt(sdev))
 		return;
 
 	/* see if the device has an echo buffer.  If it does we can
 	 * do the SPI pattern write tests */
 
 	len = 0;
-	if (sdev->ppr)
+	if (scsi_device_dt(sdev))
 		len = spi_dv_device_get_echo_buffer(sreq, buffer);
 
  retry:
@@ -828,9 +829,11 @@
 	DV_SET(period, spi_min_period(starget));
 	/* try QAS requests; this should be harmless to set if the
 	 * target supports it */
-	DV_SET(qas, 1);
+	if (scsi_device_qas(sdev))
+		DV_SET(qas, 1);
 	/* Also try IU transfers */
-	DV_SET(iu, 1);
+	if (scsi_device_ius(sdev))
+		DV_SET(iu, 1);
 	if (spi_min_period(starget) < 9) {
 		/* This u320 (or u640). Ignore the coupled parameters
 		 * like DT and IU, but set the optional ones */