ARM: at91/dt: define sam9261ek slow crystal frequency

Define at91sam9261ek's slow crystal frequencies.

Signed-off-by: Alexandre Belloni <[email protected]>
Acked-by: Boris BREZILLON <[email protected]>
Signed-off-by: Nicolas Ferre <[email protected]>

Author: alexandrebelloni

arch/arm/boot/dts/at91sam9261ek.dts

@@ -20,6 +20,10 @@
 		reg = <0x20000000 0x4000000>;
 	};
 
+	slow_xtal {
+		clock-frequency = <32768>;
+	};
+
 	main_xtal {
 		clock-frequency = <18432000>;
 	};