ARM: dts: renesas: Add RPC node to R8A779A0 V3U

The R-Car V3U does support RPC interface, however the support for it is
missing in upstream Linux DTs as of commit 9f4ad9e425a1 ("Linux 5.12"),
add the node into u-boot.dtsi to let U-Boot access the SPI NOR or HF.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
diff --git a/arch/arm/dts/r8a779a0-u-boot.dtsi b/arch/arm/dts/r8a779a0-u-boot.dtsi
index f610128..83dbe3f 100644
--- a/arch/arm/dts/r8a779a0-u-boot.dtsi
+++ b/arch/arm/dts/r8a779a0-u-boot.dtsi
@@ -7,6 +7,19 @@
 
 #include "r8a779x-u-boot.dtsi"
 
+/ {
+	soc {
+		rpc: spi@ee200000 {
+			compatible = "renesas,rpc-r8a779a0", "renesas,rcar-gen3-rpc";
+			reg = <0 0xee200000 0 0x200>, <0 0x08000000 0 0x04000000>;
+			clocks = <&cpg CPG_MOD 629>;
+			bank-width = <2>;
+			num-cs = <1>;
+			status = "disabled";
+		};
+	};
+};
+
 &extalr_clk {
 	u-boot,dm-pre-reloc;
 };