Revert "xhci: set timer to retry xfers"

This reverts commit 4e8cfbe.

We should not poll via timer, and with ccid being fixed
to properly notify us about pending transfers we don't have to.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

hw/usb/hcd-xhci.c

@@ -2222,8 +2222,6 @@ static void xhci_kick_ep(XHCIState *xhci, unsigned int slotid,
         if (xfer->running_retry) {
             DPRINTF("xhci: xfer nacked, stopping schedule\n");
             epctx->retry = xfer;
-            timer_mod(epctx->kick_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
-                      epctx->interval * 125000);
             break;
         }
     }