ARM: dts: vfxxx: Remove invalid wdog property

The 'clock-names' property is not a valid property for wdog.

Remove it to fix the following DT check warning:

vf610-zii-ssmb-dtu.dtb: watchdog@4003e000: Unevaluated properties are not allowed ('clock-names' was unexpected)
From schema: /Documentation/devicetree/bindings/watchdog/fsl-imx-wdt.yaml
Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/vfxxx.dtsi

@@ -294,7 +294,6 @@ wdoga5: watchdog@4003e000 {
 				reg = <0x4003e000 0x1000>;
 				interrupts = <20 IRQ_TYPE_LEVEL_HIGH>;
 				clocks = <&clks VF610_CLK_WDT>;
-				clock-names = "wdog";
 				status = "disabled";
 			};