arm64: dts: renesas: rzg2l-smarc-som: Enable ADC on SMARC platform

Enable the ADC which is present on RZ/G2L SMARC SOM.
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20210922212049.19851-3-prabhakar.mahadev-lad.rj@bp.renesas.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

arch/arm64/boot/dts/renesas/rzg2l-smarc-som.dtsi

@@ -5,6 +5,8 @@
  * Copyright (C) 2021 Renesas Electronics Corp.
  */
 
+#include <dt-bindings/pinctrl/rzg2l-pinctrl.h>
+
 / {
 	memory@48000000 {
 		device_type = "memory";
@@ -13,6 +15,21 @@ memory@48000000 {
 	};
 };
 
+&adc {
+	pinctrl-0 = <&adc_pins>;
+	pinctrl-names = "default";
+	status = "okay";
+
+	/delete-node/ channel@6;
+	/delete-node/ channel@7;
+};
+
 &extal_clk {
 	clock-frequency = <24000000>;
 };
+
+&pinctrl {
+	adc_pins: adc {
+		pinmux = <RZG2L_PORT_PINMUX(9, 0, 2)>; /* ADC_TRG */
+	};
+};