ARM: at91/dts: add the watchdog nodes for at91 boards

boards include:
at91sam9263ek, at91sam9g20ek, at91sam9m10g45ek, at91sam9n12ek, at91sam9x5ek

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Tested-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
diff --git a/arch/arm/boot/dts/at91sam9m10g45ek.dts b/arch/arm/boot/dts/at91sam9m10g45ek.dts
index 89c50d1..91dbf79 100644
--- a/arch/arm/boot/dts/at91sam9m10g45ek.dts
+++ b/arch/arm/boot/dts/at91sam9m10g45ek.dts
@@ -59,6 +59,10 @@
 				status = "okay";
 			};
 
+			watchdog@fffffd40 {
+				status = "okay";
+			};
+
 			mmc0: mmc@fff80000 {
 				pinctrl-0 = <
 					&pinctrl_board_mmc0