In commit c2344f13 (USB: gpio_vbus:
add delayed vbus_session calls, 2009-01-24), usb_gadget_vbus_connect()
and ...disconnect() were extracted from the interrupt handler, so to
allow vbus_session handlers to deal with msleep() calls.

This patch takes the approach one step further.

USB2.0 specification (7.1.7.3 Connect and Disconnect Signaling) says
that the USB system software (shall) provide a debounce interval with
a minimum duration of 100 ms, which ensures that the electrical and
mechanical connection is stable before software attempts to reset
the attached device.
Signed-off-by: NShinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>