arm64: dts: renesas: Add Si-Linux CAT874 board support

Basic support for the Si-Linux board based on RZ/G2E:
  - Memory,
  - Main crystal,
  - Serial console
Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Chris Paterson <Chris.Paterson2@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm64/boot/dts/renesas/Makefile

 # SPDX-License-Identifier: GPL-2.0
+dtb-$(CONFIG_ARCH_R8A774C0) += r8a774c0-cat874.dtb
 dtb-$(CONFIG_ARCH_R8A7795) += r8a7795-salvator-x.dtb r8a7795-h3ulcb.dtb
 dtb-$(CONFIG_ARCH_R8A7795) += r8a7795-h3ulcb-kf.dtb
 dtb-$(CONFIG_ARCH_R8A7795) += r8a7795-salvator-xs.dtb

arch/arm64/boot/dts/renesas/r8a774c0-cat874.dts

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Device Tree Source for the Silicon Linux RZ/G2E 96board platform (CAT874)
+ *
+ * Copyright (C) 2019 Renesas Electronics Corp.
+ */
+
+/dts-v1/;
+#include "r8a774c0.dtsi"
+
+/ {
+	model = "Silicon Linux RZ/G2E 96board platform (CAT874)";
+	compatible = "si-linux,cat874", "renesas,r8a774c0";
+
+	aliases {
+		serial0 = &scif2;
+	};
+
+	chosen {
+		bootargs = "ignore_loglevel rw root=/dev/nfs ip=dhcp";
+		stdout-path = "serial0:115200n8";
+	};
+
+	memory@48000000 {
+		device_type = "memory";
+		/* first 128MB is reserved for secure area. */
+		reg = <0x0 0x48000000 0x0 0x78000000>;
+	};
+};
+
+&extal_clk {
+	clock-frequency = <48000000>;
+};
+
+&scif2 {
+	status = "okay";
+};