arm64: dts: renesas: Add Renesas R8A779M6 SoC support

Add support for the Renesas R-Car E3e (R8A779M6) SoC, which is a
different grading of the R-Car E3 (R8A77990) SoC.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/004e837531de4160ac4815fe7836b1f05d6fad85.1628766192.git.geert+renesas@glider.be

arch/arm64/boot/dts/renesas/r8a779m6.dtsi

+// SPDX-License-Identifier: (GPL-2.0 or MIT)
+/*
+ * Device Tree Source for the R-Car E3e (R8A779M6) SoC
+ *
+ * Copyright (C) 2021 Glider bv
+ */
+
+#include "r8a77990.dtsi"
+
+/ {
+	compatible = "renesas,r8a779m6", "renesas,r8a77990";
+};