dt-bindings: tas2770: Add shutdown gpio property

Add the shutdown-gpios property to the yaml to define the GPIO that can
be used to place the device in shutdown mode or wake the device up.
Signed-off-by: Dan Murphy <dmurphy@ti.com>
Link: https://lore.kernel.org/r/20200923132600.10652-1-dmurphy@ti.comSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/tas2770.yaml

@@ -29,6 +29,9 @@ properties:
   reset-gpio:
     description: GPIO used to reset the device.
 
+  shutdown-gpios:
+    description: GPIO used to control the state of the device.
+
   interrupts:
     maxItems: 1
 
@@ -69,6 +72,7 @@ examples:
        interrupt-parent = <&gpio1>;
        interrupts = <14>;
        reset-gpio = <&gpio1 15 0>;
+       shutdown-gpios = <&gpio1 14 0>;
        ti,imon-slot-no = <0>;
        ti,vmon-slot-no = <2>;
      };