usb: chipidea: imx: Fix ULPI on imx53

Traditionally, PORTSC should be set before initializing ULPI phys. But
setting PORTSC before powering on the phy results in a kernel freeze
on imx53 based GE PPD. As a workaround this initializes the phy early
in the imx platform code and disables phy power management from the
core.

Signed-off-by: Fabien Lahoudere <fabien.lahoudere@collabora.co.uk>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Peter Chen <peter.chen@nxp.com>