ENGR00173378-1 usb: device: Change judgement condition for resume occurrence

ENGR00173378-1 usb: device: Change judgement condition for resume occurrence

At former code, it uses portsc.fpr to indicate if the host sends
resume signal to device, but it has some limitations that if the code
can't be executed before the resume signal finishes, the portsc.fpr
will be cleared automatically.
Now, it uses usbsts.pci to judge host resume signal, this bit
will not be cleared before the non-wakeup interrupt handler is called,
and the wakeup code is executed before non-wakeup interrupt handler.

Signed-off-by: Peter Chen <peter.chen@freescale.com>