ARM: at91/dt: kizbox: define main crystal frequency

Define kizbox board's main crystal frequency.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
diff --git a/arch/arm/boot/dts/kizbox.dts b/arch/arm/boot/dts/kizbox.dts
index 928f6ee..e83e4f9 100644
--- a/arch/arm/boot/dts/kizbox.dts
+++ b/arch/arm/boot/dts/kizbox.dts
@@ -30,6 +30,10 @@
 			compatible = "atmel,osc", "fixed-clock";
 			clock-frequency = <18432000>;
 		};
+
+		main_xtal {
+			clock-frequency = <18432000>;
+		};
 	};
 
 	ahb {