UHCI: no dummy TDs for Iso QHs

Isochronous queues don't need a dummy TD because the Queue Header
isn't managed by the hardware.  This patch (as836) removes the
unnecessary dummy TDs.

The patch also fixes a long-standing typo in a comment (a "don't" was
missing -- potentially very confusing!).

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/host/uhci-debug.c b/drivers/usb/host/uhci-debug.c
index b40bc1a..3fbb5ba 100644
--- a/drivers/usb/host/uhci-debug.c
+++ b/drivers/usb/host/uhci-debug.c
@@ -208,7 +208,7 @@
 					space, "", nurbs);
 	}
 
-	if (qh->udev) {
+	if (qh->dummy_td) {
 		out += sprintf(out, "%*s  Dummy TD\n", space, "");
 		out += uhci_show_td(qh->dummy_td, out, len - (out - buf), 0);
 	}