ARM: dts: imx7ulp-evk: disable usbotg1 overcurrent function

At imx7ulp evk, all USBOTG1 OC (Over Current) function pins are
used by others, and the USB driver doesn't support OC function
through the GPIO, so we disable the OC function for this board
as well as delete the pinctrl for it.

Reviewed-by: Jun Li <jun.li@nxp.com>
Acked-by: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: Peter Chen <peter.chen@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>