ARM: dts: r9a06g032: Describe the DMA router

There is a dmamux on this SoC which allows picking two different sources
for a single DMA request.
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20220427095653.91804-10-miquel.raynal@bootlin.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

arch/arm/boot/dts/r9a06g032.dtsi

@@ -92,6 +92,16 @@ sysctrl: system-controller@4000c000 {
 			clocks = <&ext_mclk>, <&ext_rtc_clk>,
 					<&ext_jtag_clk>, <&ext_rgmii_ref>;
 			clock-names = "mclk", "rtc", "jtag", "rgmii_ref_ext";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			dmamux: dma-router@a0 {
+				compatible = "renesas,rzn1-dmamux";
+				reg = <0xa0 4>;
+				#dma-cells = <6>;
+				dma-requests = <32>;
+				dma-masters = <&dma0 &dma1>;
+			};
 		};
 
 		uart0: serial@40060000 {