arm64: dts: ulcb-kf: initial device tree

Add the initial common dtsi file for Kingfisher infotainment board (R-Car
Starter Kit extension)

This commit supports the following peripherals:
- HSCIF0
Signed-off-by: Vladimir Barinov <vladimir.barinov@cogentembedded.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm64/boot/dts/renesas/ulcb-kf.dtsi

+/*
+ * Device Tree Source for the Kingfisher (ULCB extension) board
+ *
+ * Copyright (C) 2017 Renesas Electronics Corp.
+ * Copyright (C) 2017 Cogent Embedded, Inc.
+ *
+ * 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.
+ */
+
+/ {
+	aliases {
+		serial1 = &hscif0;
+	};
+};
+
+&hscif0 {
+	pinctrl-0 = <&hscif0_pins>;
+	pinctrl-names = "default";
+	uart-has-rtscts;
+
+	status = "okay";
+};
+
+&pfc {
+	hscif0_pins: hscif0 {
+		groups = "hscif0_data", "hscif0_ctrl";
+		function = "hscif0";
+	};
+};