ARM: dts: i.MX51: Fix OTG PHY clock

Proper clock ID for USB OTG PHY is "usb_phy_gate".
The patch changes this mismatch.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

arch/arm/boot/dts/imx51.dtsi

@@ -190,7 +190,7 @@ esdhc4: esdhc@70024000 {
 
 			usbphy0: usbphy@0 {
 				compatible = "usb-nop-xceiv";
-				clocks = <&clks 124>;
+				clocks = <&clks 75>;
 				clock-names = "main_clk";
 				status = "okay";
 			};