ARM: dts: rockchip: Split up rgmii1 pinctrl on rv1126

Split up the pinctrl definitions for rgmii1 so it can be shared
with devices using an RMII PHY.

Signed-off-by: Tim Lunn <tim@feathertop.org>
Link: https://lore.kernel.org/r/20231203124004.2676174-6-tim@feathertop.org


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