ARM: dts: imx28-tx28: use correct mclk frequency

The reference clock for the SGTL5000 is generated by a 26MHz crystal
oscillator on the Ka-Ro electronics STK5 eval kits. Use the correct
frequency setting in DTB.

Signed-off-by: Lothar Waßmann <[e-mail]>
Signed-off-by: Shawn Guo <[e-mail]>

arch/arm/boot/dts/imx28-tx28.dts

···
 			compatible = "fixed-clock";
 			reg = <0>;
 			#clock-cells = <0>;
-			clock-frequency = <27000000>;
+			clock-frequency = <26000000>;
 		};
 	};