usb: chipidea: host: disable io watchdog

The Chipidea EHCI core seems to behave sanely and doesn't need
the IO watchdog. This kills off 10 non-deferrable wakeup events
per second when the controller is otherwise idle.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Tested-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Peter Chen <peter.chen@nxp.com>
diff --git a/drivers/usb/chipidea/host.c b/drivers/usb/chipidea/host.c
index 053bac9..96ae695 100644
--- a/drivers/usb/chipidea/host.c
+++ b/drivers/usb/chipidea/host.c
@@ -81,12 +81,15 @@
 {
 	struct device *dev = hcd->self.controller;
 	struct ci_hdrc *ci = dev_get_drvdata(dev);
+	struct ehci_hcd *ehci = hcd_to_ehci(hcd);
 	int ret;
 
 	ret = ehci_setup(hcd);
 	if (ret)
 		return ret;
 
+	ehci->need_io_watchdog = 0;
+
 	ci_platform_configure(ci);
 
 	return ret;