arm: at91: at91sam9x5.dtsi: Add watchdog handle

This makes it possible to reference the watchdog DT node via "&watchdog"
from board dts files.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Heiko Schocher <hs@denx.de>
Cc: Andreas Bießmann <andreas@biessmann.org>
Cc: Eugen Hristev <eugen.hristev@microchip.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
diff --git a/arch/arm/dts/at91sam9x5.dtsi b/arch/arm/dts/at91sam9x5.dtsi
index ea319cc..bd4abe0 100644
--- a/arch/arm/dts/at91sam9x5.dtsi
+++ b/arch/arm/dts/at91sam9x5.dtsi
@@ -1180,7 +1180,7 @@
 				};
 			};
 
-			watchdog@fffffe40 {
+			watchdog: watchdog@fffffe40 {
 				compatible = "atmel,at91sam9260-wdt";
 				reg = <0xfffffe40 0x10>;
 				interrupts = <1 IRQ_TYPE_LEVEL_HIGH 7>;