ARM: dts: iwg20m: Add iWave RZG1M Qseven SOM

Add support for iWave RZG1M Qseven System On Module.
http://www.iwavesystems.com/rz-g1m-qseven-module.htmlSigned-off-by: Biju Das <biju.das@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/arm/boot/dts/r8a7743-iwg20m.dtsi

+/*
+ * Device Tree Source for the iWave-RZG1M-20M Qseven SOM
+ *
+ * Copyright (C) 2017 Renesas Electronics Corp.
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2.  This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+
+#include "r8a7743.dtsi"
+
+/ {
+	compatible = "iwave,g20m", "renesas,r8a7743";
+
+	memory@40000000 {
+		device_type = "memory";
+		reg = <0 0x40000000 0 0x20000000>;
+	};
+
+	memory@200000000 {
+		device_type = "memory";
+		reg = <2 0x00000000 0 0x20000000>;
+	};
+};
+
+&extal_clk {
+	clock-frequency = <20000000>;
+};