ARM: dts: stm32: Add DMAMUX support for STM32H743 SoC

This patch adds DMAMUX support for STM32H743 SoC.
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32h743.dtsi

@@ -147,6 +147,7 @@ dma1: dma@40020000 {
 			clocks = <&timer_clk>;
 			#dma-cells = <4>;
 			st,mem2mem;
+			dma-requests = <8>;
 			status = "disabled";
 		};
 
@@ -164,9 +165,20 @@ dma2: dma@40020400 {
 			clocks = <&timer_clk>;
 			#dma-cells = <4>;
 			st,mem2mem;
+			dma-requests = <8>;
 			status = "disabled";
 		};
 
+		dmamux1: dma-router@40020800 {
+			compatible = "st,stm32h7-dmamux";
+			reg = <0x40020800 0x1c>;
+			#dma-cells = <3>;
+			dma-channels = <16>;
+			dma-requests = <128>;
+			dma-masters = <&dma1 &dma2>;
+			clocks = <&timer_clk>;
+		};
+
 		adc_12: adc@40022000 {
 			compatible = "st,stm32h7-adc-core";
 			reg = <0x40022000 0x400>;