ARM: sun7i: dt: Add node to represent the DMA controller

The A20 SoC has a sun4i-compatible DMA controller. Let's add a node to
represent it on the device tree.
Signed-off-by: Emilio López <emilio@elopez.com.ar>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

arch/arm/boot/dts/sun7i-a20.dtsi

@@ -423,6 +423,14 @@ nmi_intc: interrupt-controller@01c00030 {
 			interrupts = <0 0 4>;
 		};
 
+		dma: dma-controller@01c02000 {
+			compatible = "allwinner,sun4i-a10-dma";
+			reg = <0x01c02000 0x1000>;
+			interrupts = <0 27 4>;
+			clocks = <&ahb_gates 6>;
+			#dma-cells = <2>;
+		};
+
 		spi0: spi@01c05000 {
 			compatible = "allwinner,sun4i-a10-spi";
 			reg = <0x01c05000 0x1000>;