ARM: dts: imx6dl: lanmcu: Configure over-current polarity for USB OTG node

This commit adds the 'over-current-active-low' flag to the USB OTG node
in the imx6dl-lanmcu device tree. This flag is necessary because the
hardware signals over-current conditions by pulling the line low.
Without this flag, the kernel could misinterpret an over-current
condition, leading to unexpected behavior.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>