ENGR00169661:Remove the discharge for VBUS and DP

ENGR00169661:Remove the discharge for VBUS and DP

- VBUS discharge code should be removed from suspend_irq function
- On Arik, there is a huge capacitance(C86), even discharge VBUS,
  the Drop of VBUS is still very slow
- On Arik, the B session valid threshold is not 0.8V or 1.4V, it is
  about 2V~3V, so we can receive B session valid interrupt very soon
- No DP discharge needed, but wait for SE0 is needed
Signed-off-by: Tony LIU <junjie.liu@freescale.com>