usb: phy: omap-usb2: Don't use omap_get_control_dev()

omap_get_control_dev() is being deprecated as it doesn't support
multiple instances. As control device is present only from OMAP4
onwards which supports DT only, we use phandles to get the
reference to the control device.

As we don't support non-DT boot, we just bail out on probe
if device node is not present.

Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>