arm64: dts: allwinner: h5: OrangePi PC2: Fix ethernet node

RX and TX delay are provided by ethernet PHY. Reflect that in ethernet
node.

Fixes: 44a94c7e ("arm64: dts: allwinner: H5: Restore EMAC changes")
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20201023184858.3272918-1-jernej.skrabec@siol.net