arm64: dts: renesas: falcon: Add Ethernet sub-board

Add a DTS file for the Falcon Ethernet sub-board (RTP0RC779A0ETS0010S),
and include it from the main r8a779a0-falcon.dts.

For now its contents are limited to the Board ID EEPROM.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20210304153257.4059277-4-geert+renesas@glider.be

arch/arm64/boot/dts/renesas/r8a779a0-falcon-ethernet.dtsi

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Device Tree Source for the Falcon Ethernet sub-board
+ *
+ * Copyright (C) 2021 Glider bv
+ */
+
+&i2c0 {
+	eeprom@53 {
+		compatible = "rohm,br24g01", "atmel,24c01";
+		label = "ethernet-sub-board-id";
+		reg = <0x53>;
+		pagesize = <8>;
+	};
+};

arch/arm64/boot/dts/renesas/r8a779a0-falcon.dts

@@ -8,6 +8,7 @@
 /dts-v1/;
 #include "r8a779a0-falcon-cpu.dtsi"
 #include "r8a779a0-falcon-csi-dsi.dtsi"
+#include "r8a779a0-falcon-ethernet.dtsi"
 
 / {
 	model = "Renesas Falcon CPU and Breakout boards based on r8a779a0";