ARM: dts: i.MX27: Using "wdog_ipg_gate" clock source for watchdog

Patch replaces "dummy" clock source for watchdog with "wdog_ipg_gate".
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

arch/arm/boot/dts/imx27.dtsi

@@ -96,7 +96,7 @@ wdog: wdog@10002000 {
 				compatible = "fsl,imx27-wdt", "fsl,imx21-wdt";
 				reg = <0x10002000 0x1000>;
 				interrupts = <27>;
-				clocks = <&clks 0>;
+				clocks = <&clks 74>;
 			};
 
 			gpt1: timer@10003000 {