dt-bindings: mfd: mediatek: Add codec property for MT6357 PMIC

Add the audio codec sub-device. This sub-device is used to set the
optional voltage values according to the hardware.
The properties are:
  - Setup of microphone bias voltage.
  - Setup of the speaker pin pull-down.

Also, add the audio power supply property which is dedicated for
the audio codec sub-device.

Signed-off-by: Alexandre Mergnat <amergnat@baylibre.com>
Link: https://patch.msgid.link/20240226-audio-i350-v7-3-6518d953a141@baylibre.com
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/mfd/mediatek,mt6357.yaml

@@ -37,6 +37,24 @@ properties:
   "#interrupt-cells":
     const: 2
 
+  mediatek,hp-pull-down:
+    description:
+      Earphone driver positive output stage short to
+      the audio reference ground.
+    type: boolean
+
+  mediatek,micbias0-microvolt:
+    description: Selects MIC Bias 0 output voltage.
+    enum: [1700000, 1800000, 1900000, 2000000,
+           2100000, 2500000, 2600000, 2700000]
+    default: 1700000
+
+  mediatek,micbias1-microvolt:
+    description: Selects MIC Bias 1 output voltage.
+    enum: [1700000, 1800000, 1900000, 2000000,
+           2100000, 2500000, 2600000, 2700000]
+    default: 1700000
+
   regulators:
     type: object
     $ref: /schemas/regulator/mediatek,mt6357-regulator.yaml
@@ -83,6 +101,9 @@ examples:
             interrupt-controller;
             #interrupt-cells = <2>;
 
+            mediatek,micbias0-microvolt = <1700000>;
+            mediatek,micbias1-microvolt = <1700000>;
+
             regulators {
                 mt6357_vproc_reg: buck-vproc {
                     regulator-name = "vproc";