ASoC: dt-bindings: update cs42l51 bindings

Add compatible, reg, regulator, and reset
to Cirrus CS42L51 audio codec bindings.
Signed-off-by: NOlivier Moysan <olivier.moysan@st.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/cs42l51.txt

 CS42L51 audio CODEC
 
+Required properties:
+
+  - compatible : "cirrus,cs42l51"
+
+  - reg : the I2C address of the device for I2C.
+
 Optional properties:
+  - VL-supply, VD-supply, VA-supply, VAHP-supply: power supplies for the device,
+    as covered in Documentation/devicetree/bindings/regulator/regulator.txt.
+
+  - reset-gpios : GPIO specification for the reset pin. If specified, it will be
+    deasserted before starting the communication with the codec.
 
   - clocks : a list of phandles + clock-specifiers, one for each entry in
     clock-names
@@ -14,4 +25,9 @@ cs42l51: cs42l51@4a {
 	reg = <0x4a>;
 	clocks = <&mclk_prov>;
 	clock-names = "MCLK";
+	VL-supply = <&reg_audio>;
+	VD-supply = <&reg_audio>;
+	VA-supply = <&reg_audio>;
+	VAHP-supply = <&reg_audio>;
+	reset-gpios = <&gpiog 9 GPIO_ACTIVE_LOW>;
 };