ARM: dts: imx6sx: specify proper clock for nodes with dummy clock

From i.MX6SX reference manual CCM chapter, KPP and
WDOGn use IPG clock as their clock, specify IPG
clock for KPP and WDOGn instead of DUMMY clock.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx6sx.dtsi

@@ -558,7 +558,7 @@ kpp: kpp@20b8000 {
 				compatible = "fsl,imx6sx-kpp", "fsl,imx21-kpp";
 				reg = <0x020b8000 0x4000>;
 				interrupts = <GIC_SPI 82 IRQ_TYPE_LEVEL_HIGH>;
-				clocks = <&clks IMX6SX_CLK_DUMMY>;
+				clocks = <&clks IMX6SX_CLK_IPG>;
 				status = "disabled";
 			};
 
@@ -566,14 +566,14 @@ wdog1: wdog@20bc000 {
 				compatible = "fsl,imx6sx-wdt", "fsl,imx21-wdt";
 				reg = <0x020bc000 0x4000>;
 				interrupts = <GIC_SPI 80 IRQ_TYPE_LEVEL_HIGH>;
-				clocks = <&clks IMX6SX_CLK_DUMMY>;
+				clocks = <&clks IMX6SX_CLK_IPG>;
 			};
 
 			wdog2: wdog@20c0000 {
 				compatible = "fsl,imx6sx-wdt", "fsl,imx21-wdt";
 				reg = <0x020c0000 0x4000>;
 				interrupts = <GIC_SPI 81 IRQ_TYPE_LEVEL_HIGH>;
-				clocks = <&clks IMX6SX_CLK_DUMMY>;
+				clocks = <&clks IMX6SX_CLK_IPG>;
 				status = "disabled";
 			};
 
@@ -1270,7 +1270,7 @@ wdog3: wdog@2288000 {
 				compatible = "fsl,imx6sx-wdt", "fsl,imx21-wdt";
 				reg = <0x02288000 0x4000>;
 				interrupts = <GIC_SPI 11 IRQ_TYPE_LEVEL_HIGH>;
-				clocks = <&clks IMX6SX_CLK_DUMMY>;
+				clocks = <&clks IMX6SX_CLK_IPG>;
 				status = "disabled";
 			};