arm64: dts: renesas: rzg2lc: Set Ethernet PVDD to 1.8V

arm64: dts: renesas: rzg2lc: Set Ethernet PVDD to 1.8V

On the RZ/G2LC SMARC SOM, the RGMII interface between the SoC and the
Ethernet PHY operates at 1.8V.

The power supply for this interface may be correctly configured in
u-boot, but the kernel should not be relying on this. Now that the
RZ/G2L pinctrl driver supports configuring the Ethernet power supply
voltage, we can simply specify the desired voltage in the device tree.

Signed-off-by: Paul Barker <paul.barker.ct@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/20240625200316.4282-9-paul.barker.ct@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>