usb: dwc3: gadget: set gadgets parent to the right controller

In case of dwc3 it is possible that the sysdev is the parent of the
controller. To ensure the right dev is set to the gadget's dev parent we
will hand over sysdev instead of dev, which will always point to the
controller.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Link: https://lore.kernel.org/r/20210628155311.16762-2-m.grzeschik@pengutronix.de


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>