arm64: dts: renesas: r8a779g2: Add White Hawk Single support

The White Hawk Single board is a single-board integration of the Renesas
White Hawk CPU and Breakout board stack, based on the R-Car V4H ES2.0
(R8A779G2) SoC.

For now, the only visible differences compared to the board stack are:
  - The SoC is an updated version of R-Car V4H (R8A779G0),
  - The serial console uses an FT2232H instead of a CP2102 USB-UART
    bridge, with CTS/RTS wired.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/2b8d37949c17cca170c1d9e97f10a100b20c5cd9.1706192990.git.geert+renesas@glider.be

arch/arm64/boot/dts/renesas/Makefile

@@ -87,6 +87,8 @@ dtb-$(CONFIG_ARCH_R8A779G0) += r8a779g0-white-hawk-ard-audio-da7212.dtbo
 r8a779g0-white-hawk-ard-audio-da7212-dtbs := r8a779g0-white-hawk.dtb r8a779g0-white-hawk-ard-audio-da7212.dtbo
 dtb-$(CONFIG_ARCH_R8A779G0) += r8a779g0-white-hawk-ard-audio-da7212.dtb
 
+dtb-$(CONFIG_ARCH_R8A779G0) += r8a779g2-white-hawk-single.dtb
+
 dtb-$(CONFIG_ARCH_R8A77951) += r8a779m1-salvator-xs.dtb
 r8a779m1-salvator-xs-panel-aa104xd12-dtbs := r8a779m1-salvator-xs.dtb salvator-panel-aa104xd12.dtbo
 dtb-$(CONFIG_ARCH_R8A77951) += r8a779m1-salvator-xs-panel-aa104xd12.dtb

arch/arm64/boot/dts/renesas/r8a779g2-white-hawk-single.dts

+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+/*
+ * Device Tree Source for the R-Car V4H ES2.0 White Hawk Single board
+ *
+ * Copyright (C) 2023 Glider bv
+ */
+
+/dts-v1/;
+#include "r8a779g2.dtsi"
+#include "white-hawk-cpu-common.dtsi"
+#include "white-hawk-common.dtsi"
+
+/ {
+	model = "Renesas White Hawk Single board based on r8a779g2";
+	compatible = "renesas,white-hawk-single", "renesas,r8a779g2",
+		     "renesas,r8a779g0";
+};
+
+&hscif0 {
+	uart-has-rtscts;
+};
+
+&hscif0_pins {
+	groups = "hscif0_data", "hscif0_ctrl";
+	function = "hscif0";
+};