ARM: dts: imx6ul: specify proper clocks for GPT node

The i.MX6UL GPT unit requires real clocks. Define the appropriate
clocks to make it work.
Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx6ul.dtsi

@@ -499,8 +499,8 @@ gpt2: gpt@020e8000 {
 				compatible = "fsl,imx6ul-gpt", "fsl,imx6sx-gpt";
 				reg = <0x020e8000 0x4000>;
 				interrupts = <GIC_SPI 109 IRQ_TYPE_LEVEL_HIGH>;
-				clocks = <&clks IMX6UL_CLK_DUMMY>,
-					 <&clks IMX6UL_CLK_DUMMY>;
+				clocks = <&clks IMX6UL_CLK_GPT2_BUS>,
+					 <&clks IMX6UL_CLK_GPT2_SERIAL>;
 				clock-names = "ipg", "per";
 			};