ASoC: tfa9879: clean up bindings

Fix a couple of nitpicks:

- list #sound-dai-cells as a required property.
- The chip supports full speed I2C; don't indicate standard mode only.
- status = "okay" is just noise.
- The chip is an amplifier, not a codec.
- consistently indent with tabs.

Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/tfa9879.txt

@@ -6,18 +6,18 @@ Required properties:
 
 - reg : the I2C address of the device
 
+- #sound-dai-cells : must be 0.
+
 Example:
 
 &i2c1 {
-	clock-frequency = <100000>;
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_i2c1>;
-	status = "okay";
 
-	codec: tfa9879@6c {
+	amp: amp@6c {
 		#sound-dai-cells = <0>;
 		compatible = "nxp,tfa9879";
 		reg = <0x6c>;
-        };
+	};
 };