ENGR00325832 usb: chipidea: usb vbus glitch check logic change

ENGR00325832 usb: chipidea: usb vbus glitch check logic change

This patch changes the vbus glitch check to cover usb otg certification
case, so the possible cases of vbus rise:
- USB vbus can reach AVV(4.4v), valid vbus.
- USB vbus keeps above BSV(0.8v) but lower than AVV(4.4v) for
  more than 300ms, we think it's valid vbus event, this can meet
  usb otg certificataion case(B device can do connection in 1s when
  vbus is 4.0v).
- USB vbus cannot be kept above BSV(0.8v) for more than 300ms,
  it's a vbus glitch.
In case of vbus drop: if the vbus on flag is not set, it's a vbus glitch,
otherwise it's a valid vbus drop event.

Acked-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Li Jun <b47624@freescale.com>
(cherry picked from commit de5ab444839b6d1492d697256ea2b8a1dcaffc62)