ARM: dts: imx51-babbage: Use predefined constants for clock definition

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>

arch/arm/boot/dts/imx51-babbage.dts

@@ -170,7 +170,7 @@ usbphy {
 		usbh1phy: usbh1phy@0 {
 			compatible = "usb-nop-xceiv";
 			reg = <0>;
-			clocks = <&clks 0>;
+			clocks = <&clks IMX5_CLK_DUMMY>;
 			clock-names = "main_clk";
 		};
 	};