[nrf fromlist] dts: common: nordic: nRF54L20: add audio clock node

Added binding and node for audio clock on nRF54L20
with fixed frequency of 24 MHz.

Upstream PR #: 87105

Signed-off-by: Michał Stasiak <[email protected]>

Author: mstasiaknordic

dts/bindings/clock/nordic,nrf-aclk.yaml

@@ -0,0 +1,14 @@
+# Copyright (c) 2025 Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+
+description: Nordic Audio clock node
+
+compatible: "nordic,nrf-aclk"
+
+include: fixed-clock.yaml
+
+properties:
+  clock-frequency:
+    type: int
+    description: |
+      Frequency of the Audio clock in Hz.

dts/common/nordic/nrf54l20.dtsi

@@ -76,6 +76,12 @@
 			#clock-cells = <0>;
 			clock-frequency = <DT_FREQ_M(128)>;
 		};
+
+		aclk: aclk {
+			compatible = "nordic,nrf-aclk";
+			#clock-cells = <0>;
+			clock-frequency = <DT_FREQ_M(24)>;
+		};
 	};
 
 	soc {