arm64: dts: rockchip: Correct gmac phy address on QNAP TS433

The Motorcomm Phy can be talked to on mdio broadcast address 0, but the
actuall address is 3. Adapt the reg property and node name accordingly.

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/6b8ef7e37e646f4cd399ceb2f46017644d76da9d.1742331667.git.ukleinek@kernel.org


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