lantiq: danube fxs bugfix: changed compatible attribute of vmmc

This bugfix enables FXS support on dabube based devices.
Changed "compatible" attribute from "vmmc" to "vmmc-xway".
The vmmc driver uses "vmmc-xway".

Signed-off-by: Stefan Koch <stefan.koch10@gmail.com>

target/linux/lantiq/dts/danube.dtsi

@@ -73,7 +73,7 @@
 
 		vmmc@107000 {
 			status = "disabled";
-			compatible = "lantiq,vmmc";
+			compatible = "lantiq,vmmc-xway";
 			reg = <0x103000 0x400>;
 			interrupt-parent = <&icu0>;
 			interrupts = <150 151 152 153 154 155>;