arm64: dts: allwinner: h6: orangepi-one-plus: Fix ethernet

RX/TX delay on OrangePi One Plus board is set on PHY. Reflect that in
ethernet node.

Fixes: 7ee32a17 ("arm64: dts: allwinner: h6: orangepi-one-plus: Enable ethernet")
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Tested-by: Marcus Cooper <codekipper@gmail.com>
Link: https://lore.kernel.org/r/20201101072609.1681891-1-jernej.skrabec@siol.net