ENGR00286426-16 usb: chipidea: usbmisc_imx: remove the controller's clock info

ENGR00286426-16 usb: chipidea: usbmisc_imx: remove the controller's clock info

Currently, the usbmisc is just an API supplier for controller
driver, the controller calls related APIs to handle different
things among the SoCs, before calling it, the clock must
be on. So the clock operation is useless for usbmisc, it also
increases the difficulties to manage the clock, especially at
runtime power management situation.

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