arm64: dts: renesas: white-hawk: Add Ethernet sub-board

Add a DTS file for the R-Car V4H White Hawk RAVB/Ethernet(1000Base-T1)
sub-board (RTP8A779G0ASKB0SE0SA000), and include it from the main
r8a779g0-white-hawk.dts.

For now its contents are limited to the Board ID EEPROM.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/991600919513dd05a9a7d9c170c6924baf14d1a2.1662715538.git.geert+renesas@glider.be

arch/arm64/boot/dts/renesas/r8a779g0-white-hawk-ethernet.dtsi

+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+/*
+ * Device Tree Source for the R-Car V4H White Hawk RAVB/Ethernet(1000Base-T1)
+ * sub-board
+ *
+ * Copyright (C) 2022 Glider bv
+ */
+
+&i2c0 {
+	eeprom@53 {
+		compatible = "rohm,br24g01", "atmel,24c01";
+		label = "ethernet-sub-board-id";
+		reg = <0x53>;
+		pagesize = <8>;
+	};
+};

arch/arm64/boot/dts/renesas/r8a779g0-white-hawk.dts

@@ -8,6 +8,7 @@
 /dts-v1/;
 #include "r8a779g0-white-hawk-cpu.dtsi"
 #include "r8a779g0-white-hawk-csi-dsi.dtsi"
+#include "r8a779g0-white-hawk-ethernet.dtsi"
 
 / {
 	model = "Renesas White Hawk CPU and Breakout boards based on r8a779g0";