ARM: shmobile: kzm9g-reference: Common clock framework DT description

KZM9G-specific clock overrides.
Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/sh73a0-kzm9g-reference.dts

@@ -182,6 +182,10 @@ &cmt1 {
 	status = "ok";
 };
 
+&extal2_clk {
+	clock-frequency = <48000000>;
+};
+
 &i2c0 {
 	status = "okay";
 	as3711@40 {