usb: ohci: fix error return code in servicing td

It should return 1 if an error occurs when reading td.
This will avoid an infinite loop issue in ohci_service_ed_list.
Signed-off-by: NLi Qiang <liqiang6-s@360.cn>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 1487760990-115925-1-git-send-email-liqiang6-s@360.cn
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

hw/usb/hcd-ohci.c

@@ -1001,7 +1001,7 @@ static int ohci_service_td(OHCIState *ohci, struct ohci_ed *ed)
     if (ohci_read_td(ohci, addr, &td)) {
         trace_usb_ohci_td_read_error(addr);
         ohci_die(ohci);
-        return 0;
+        return 1;
     }
 
     dir = OHCI_BM(ed->flags, ED_D);