usb: dwc2: add bus_suspend/bus_resume for dwc2

Change-Id: I6296d3829b5958277ec484aeadfe163cfc254108
Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Merge branch '3.14_kernel' of https://github.com/rkchrome/kernel into 3.14_kernel