ARM: dts: imx6ul-14x14-evk: add USB dual-role support

With commit 851ce932 ("usb: chipidea: otg: don't wait vbus
drops below BSV when starts host"), the driver can support
enabling vbus output without software control, so this board
(control vbus output through ID pin) can support dual-role now.

Signed-off-by: Peter Chen <peter.chen@nxp.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>