ARM: dts: at91: add io-channel-cells to adc node

Add io-channel-cell to ADC node. It is necessary for DT users of ADC.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>

Author: claudiubeznea

arch/arm/boot/dts/sama7g5.dtsi

@@ -511,6 +511,7 @@
 			atmel,min-sample-rate-hz = <200000>;
 			atmel,max-sample-rate-hz = <20000000>;
 			atmel,startup-time-ms = <4>;
+			#io-channel-cells = <1>;
 			status = "disabled";
 		};