usb: ehci: Do not disable an already disabled periodic schedule

When periodic_schedules == 0, the schedule is disabled and there is no reason
to disable it again.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 936d006..55f4436 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -1249,9 +1249,11 @@
 			   ALIGN_END_ADDR(struct qTD, result->tds,
 					  queuesize));
 
-	if (disable_periodic(ctrl) < 0) {
-		debug("FATAL: periodic should never fail, but did");
-		goto fail3;
+	if (ctrl->periodic_schedules > 0) {
+		if (disable_periodic(ctrl) < 0) {
+			debug("FATAL: periodic should never fail, but did");
+			goto fail3;
+		}
 	}
 
 	/* hook up to periodic list */