USB: set hub's default autosuspend delay as 0

	desc = intf->cur_altsetting;

	hdev = interface_to_usbdev(intf);

	/*

	 * Set default autosuspend delay as 0 to speedup bus suspend,

	 * based on the below considerations:

	 *

	 * - Unlike other drivers, the hub driver does not rely on the

	 *   autosuspend delay to provide enough time to handle a wakeup

	 *   event, and the submitted status URB is just to check future

	 *   change on hub downstream ports, so it is safe to do it.

	 *

	 * - The patch might cause one or more auto supend/resume for

	 *   below very rare devices when they are plugged into hub

	 *   first time:

	 *

	 *   	devices having trouble initializing, and disconnect

	 *   	themselves from the bus and then reconnect a second

	 *   	or so later

	 *

	 *   	devices just for downloading firmware, and disconnects

	 *   	themselves after completing it

	 *

	 *   For these quite rare devices, their drivers may change the

	 *   autosuspend delay of their parent hub in the probe() to one

	 *   appropriate value to avoid the subtle problem if someone

	 *   does care it.

	 *

	 * - The patch may cause one or more auto suspend/resume on

	 *   hub during running 'lsusb', but it is probably too

	 *   infrequent to worry about.

	 *

	 * - Change autosuspend delay of hub can avoid unnecessary auto

	 *   suspend timer for hub, also may decrease power consumption

	 *   of USB bus.

	 */

	pm_runtime_set_autosuspend_delay(&hdev->dev, 0);

	/* Hubs have proper suspend/resume support. */

	usb_enable_autosuspend(hdev);