ASoC: dt-bindings: wlf,wm8978: Fix I2C address in example

According to the WM8978 datasheet, the address of the device is fixed as
0011010 in 2-wire mode.

Fixes: 5bd5699c ("ASoC: dt-bindings: Add WM8978 Binding")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/c99fc865e3fca6ea623661c52de7dc6a3c36c8b4.1632487554.git.geert+renesas@glider.beSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/wlf,wm8978.yaml

@@ -48,10 +48,10 @@ examples:
         #address-cells = <1>;
         #size-cells = <0>;
 
-        codec@0 {
+        codec@1a {
             #sound-dai-cells = <0>;
             compatible = "wlf,wm8978";
-            reg = <0>;
+            reg = <0x1a>;
         };
     };