ARM: at91: add pmc DT support

Specified the main Oscillator via clock binding.
This will allow to do not hardcode it anymore in the DT board at 12MHz.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
diff --git a/arch/arm/boot/dts/at91sam9x5cm.dtsi b/arch/arm/boot/dts/at91sam9x5cm.dtsi
index 5b37033..67936f8 100644
--- a/arch/arm/boot/dts/at91sam9x5cm.dtsi
+++ b/arch/arm/boot/dts/at91sam9x5cm.dtsi
@@ -12,6 +12,17 @@
 		reg = <0x20000000 0x8000000>;
 	};
 
+	clocks {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges;
+
+		main_clock: clock@0 {
+			compatible = "atmel,osc", "fixed-clock";
+			clock-frequency = <12000000>;
+		};
+	};
+
 	ahb {
 		nand0: nand@40000000 {
 			nand-bus-width = <8>;