ARM: dts: vf: align watchdog node name with dtschema

The dtschema expects watchdog device node name to be "watchdog":

  arch/arm/boot/dts/vf500-colibri-eval-v3.dt.yaml: wdog@4003e000:
    $nodename:0: 'wdog@4003e000' does not match '^watchdog(@.*|-[0-9a-f])?$'
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/vfxxx.dtsi

@@ -293,7 +293,7 @@ tcon0: timing-controller@4003d000 {
 				status = "disabled";
 			};
 
-			wdoga5: wdog@4003e000 {
+			wdoga5: watchdog@4003e000 {
 				compatible = "fsl,vf610-wdt", "fsl,imx21-wdt";
 				reg = <0x4003e000 0x1000>;
 				interrupts = <20 IRQ_TYPE_LEVEL_HIGH>;