ARM: mxs: saif0 is the clock provider to sgtl5000

These systems all use saif0 as the mclock provider to codec sgtl5000.
Reflect that in device tree source, so that sgtl5000 can find the clock
by calling clk_get().

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

arch/arm/boot/dts/imx28.dtsi

@@ -837,6 +837,7 @@
 				compatible = "fsl,imx28-saif";
 				reg = <0x80042000 0x2000>;
 				interrupts = <59 80>;
+				#clock-cells = <0>;
 				clocks = <&clks 53>;
 				dmas = <&dma_apbx 4>;
 				dma-names = "rx-tx";