ARM: shmobile: koelsch: use CCF for audio clock

Because of historical reason, audio clock didn't use CCF.
Let's use it now.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a7791-koelsch.dts

@@ -242,6 +242,13 @@
 			  1800000 0>;
 	};
 
+	audio_clock: clock {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <11289600>;
+		clock-output-names = "audio_clock";
+	};
+
 	rsnd_ak4643: sound {
 		compatible = "simple-audio-card";
 
@@ -255,7 +262,7 @@
 
 		sndcodec: simple-audio-card,codec {
 			sound-dai = <&ak4643>;
-			system-clock-frequency = <11289600>;
+			clocks = <&audio_clock>;
 		};
 	};