ASoC: google: dt-bindings: add new compatible for sc7180-coachz

Add devicetree bindings for coachz in documentation file
Signed-off-by: Nxuyuqing <xuyuqing@huaqin.corp-partner.google.com>
Link: https://lore.kernel.org/r/20201112014328.695232-2-xuyuqing@huaqin.corp-partner.google.comSigned-off-by: NMark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/google,sc7180-trogdor.yaml

@@ -15,7 +15,9 @@ description:
 
 properties:
   compatible:
-    const: google,sc7180-trogdor
+    enum:
+      - google,sc7180-trogdor
+      - google,sc7180-coachz
 
   audio-routing:
     $ref: /schemas/types.yaml#/definitions/non-unique-string-array