wusb: return -ENOTCONN when resetting a port with no connected device

If reading the device descriptor fails during hub_port_init() fails,
then the port is disabled, disconnecting the device.  The port is then
reset at the start of the next init attempt but there is no device to
reset.

Signed-off-by: David Vrabel <david.vrabel@csr.com>
diff --git a/drivers/usb/wusbcore/devconnect.c b/drivers/usb/wusbcore/devconnect.c
index e2e7e4b..8e18141 100644
--- a/drivers/usb/wusbcore/devconnect.c
+++ b/drivers/usb/wusbcore/devconnect.c
@@ -386,6 +386,7 @@
 			  | USB_PORT_STAT_LOW_SPEED | USB_PORT_STAT_HIGH_SPEED);
 	port->change |= USB_PORT_STAT_C_CONNECTION | USB_PORT_STAT_C_ENABLE;
 	if (wusb_dev) {
+		dev_dbg(wusbhc->dev, "disconnecting device from port %d\n", wusb_dev->port_idx);
 		if (!list_empty(&wusb_dev->cack_node))
 			list_del_init(&wusb_dev->cack_node);
 		/* For the one in cack_add() */