arm64: dts: rockchip: Simplify network PHY connection on qnap-ts433

While it requires to have the right phy driver loaded (i.e. motorcomm)
to make the phy asserting the right delays, this is generally the
preferred way to define the MAC <-> PHY connection.

Signed-off-by: Uwe Kleine-König <ukleinek@debian.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20240304084612.711678-2-ukleinek@debian.org


Signed-off-by: Heiko Stuebner <heiko@sntech.de>