arm64: dts: rockchip: add SARADC to rock-5a

Enable ADC support for Rock 5A, which has the following ADC channels:

Channel 0 = Boot Mode Config
Channel 1 = Recovery Key
Channel 2 = PWM Fan
Channel 3 = Headphone Hook
Channel 4 = System Input Voltage
Channel 5 = Board ID Config
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://lore.kernel.org/r/20230710165228.105983-13-sebastian.reichel@collabora.comSigned-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm64/boot/dts/rockchip/rk3588s-rock-5a.dts

@@ -286,6 +286,11 @@ rtl8211f_rst: rtl8211f-rst {
 	};
 };
 
+&saradc {
+	vref-supply = <&avcc_1v8_s0>;
+	status = "okay";
+};
+
 &sdhci {
 	bus-width = <8>;
 	no-sdio;