ARM: dts: da850: use new 'dma-channels' property

The '#dma-channels' property was deprecated in favor of one defined by
generic dma-common DT bindings.  Add new property while keeping old one
for backwards compatibility.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220516142857.6419-3-krzysztof.kozlowski@linaro.org'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/boot/dts/da850.dtsi

@@ -679,7 +679,9 @@ cppi41dma: dma-controller@201000 {
 					    "scheduler", "queuemgr";
 				interrupts = <58>;
 				#dma-cells = <2>;
+				/* For backwards compatibility: */
 				#dma-channels = <4>;
+				dma-channels = <4>;
 				power-domains = <&psc1 1>;
 				status = "okay";
 			};