arm64: dts: renesas: Add support for Salvator-XS with R-Car M3-W+

Add initial support for the Renesas Salvator-X 2nd version development
board equipped with an R-Car M3-W+ SiP with 8 (2 x 4) GiB of RAM.

The memory map is as follows:
  - Bank0: 4GiB RAM : 0x000048000000 -> 0x000bfffffff
		      0x000480000000 -> 0x004ffffffff
  - Bank1: 4GiB RAM : 0x000600000000 -> 0x006ffffffff

Based on a patch in the BSP by Takeshi Kihara
<takeshi.kihara.df@renesas.com>.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20191023123342.13100-10-geert+renesas@glider.be

arch/arm64/boot/dts/renesas/Makefile

@@ -15,6 +15,7 @@ dtb-$(CONFIG_ARCH_R8A7796) += r8a7796-salvator-xs.dtb
 dtb-$(CONFIG_ARCH_R8A77960) += r8a7796-salvator-x.dtb r8a7796-m3ulcb.dtb
 dtb-$(CONFIG_ARCH_R8A77960) += r8a7796-m3ulcb-kf.dtb
 dtb-$(CONFIG_ARCH_R8A77960) += r8a7796-salvator-xs.dtb
+dtb-$(CONFIG_ARCH_R8A77961) += r8a77961-salvator-xs.dtb
 dtb-$(CONFIG_ARCH_R8A77965) += r8a77965-salvator-x.dtb r8a77965-salvator-xs.dtb
 dtb-$(CONFIG_ARCH_R8A77965) += r8a77965-m3nulcb.dtb
 dtb-$(CONFIG_ARCH_R8A77965) += r8a77965-m3nulcb-kf.dtb

arch/arm64/boot/dts/renesas/r8a77961-salvator-xs.dts

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Device Tree Source for the Salvator-X 2nd version board with R-Car M3-W+
+ *
+ * Copyright (C) 2018 Renesas Electronics Corp.
+ */
+
+/dts-v1/;
+#include "r8a77961.dtsi"
+#include "salvator-xs.dtsi"
+
+/ {
+	model = "Renesas Salvator-X 2nd version board based on r8a77961";
+	compatible = "renesas,salvator-xs", "renesas,r8a77961";
+
+	memory@48000000 {
+		device_type = "memory";
+		/* first 128MB is reserved for secure area. */
+		reg = <0x0 0x48000000 0x0 0x78000000>;
+	};
+
+	memory@400000000 {
+		device_type = "memory";
+		reg = <0x4 0x80000000 0x0 0x80000000>;
+	};
+
+	memory@600000000 {
+		device_type = "memory";
+		reg = <0x6 0x00000000 0x1 0x00000000>;
+	};
+};