usb: ulpi: move setting of ulpi->dev parent up in ulpi_register()

Once ulpi operations use the parent device directly, this will be
needed during the operations used in ulpi_register() itself, so set
the parent field before calling any ulpi operations.

Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Tal Shorer <tal.shorer@gmail.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>