arm64: dts: mediatek: Add OpenWrt One

OpenWrt One is the first ever OpenWrt product. It's based on MT7981B
(AKA Filogic 820) and has 1 GiB or DDR4 RAM. The rest of peripherals
remains to be added later.
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20240527115933.7396-4-zajec5@gmail.comSigned-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

arch/arm64/boot/dts/mediatek/Makefile

@@ -9,6 +9,7 @@ dtb-$(CONFIG_ARCH_MEDIATEK) += mt6797-x20-dev.dtb
 dtb-$(CONFIG_ARCH_MEDIATEK) += mt7622-rfb1.dtb
 dtb-$(CONFIG_ARCH_MEDIATEK) += mt7622-bananapi-bpi-r64.dtb
 dtb-$(CONFIG_ARCH_MEDIATEK) += mt7981b-cudy-wr3000-v1.dtb
+dtb-$(CONFIG_ARCH_MEDIATEK) += mt7981b-openwrt-one.dtb
 dtb-$(CONFIG_ARCH_MEDIATEK) += mt7981b-xiaomi-ax3000t.dtb
 dtb-$(CONFIG_ARCH_MEDIATEK) += mt7986a-acelink-ew-7886cax.dtb
 dtb-$(CONFIG_ARCH_MEDIATEK) += mt7986a-bananapi-bpi-r3.dtb

arch/arm64/boot/dts/mediatek/mt7981b-openwrt-one.dts

+// SPDX-License-Identifier: GPL-2.0-only OR MIT
+
+/dts-v1/;
+
+#include "mt7981b.dtsi"
+
+/ {
+	compatible = "openwrt,one", "mediatek,mt7981b";
+	model = "OpenWrt One";
+
+	memory@40000000 {
+		reg = <0 0x40000000 0 0x40000000>;
+		device_type = "memory";
+	};
+};