ARM: at91/dt: tny_a9260: define crystals frequencies

Define Calao TNY-A9260 and TNY-A9G20 main and slow crystals frequencies.
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: NNicolas Ferre <nicolas.ferre@atmel.com>

arch/arm/boot/dts/tny_a9260_common.dtsi

@@ -24,6 +24,14 @@
 			compatible = "atmel,osc", "fixed-clock";
 			clock-frequency = <12000000>;
 		};
+
+		slow_xtal {
+			clock-frequency = <32768>;
+		};
+
+		main_xtal {
+			clock-frequency = <12000000>;
+		};
 	};
 
 	ahb {