ENGR00220440 Mx6:USB device: clear OWIE before phy out of low power mode

ENGR00220440 Mx6:USB device: clear OWIE before phy out of low power mode

There is a limitation on mx6 phy low power flow. During phy enter low power mode
and out of low power mode with OWIE bit active,there will be abnormal usb wakeup
interrupt happen. So we should clear OWIE bit before phy out of low power mode.

Signed-off-by: make shi <b15407@freescale.com>