ASoC: dt-bindings: mt8183-da7219: add compatible string for using rt1015p

Machines with rt1015p should use the compatible string
"mediatek,mt8183_da7219_rt1015p".
Signed-off-by: Tzung-Bi Shih <tzungbi@google.com>
Link: https://lore.kernel.org/r/20200911024833.1673961-2-tzungbi@google.comSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/mt8183-da7219-max98357.txt

@@ -3,6 +3,7 @@ MT8183 with MT6358, DA7219, MAX98357, and RT1015 CODECS
 Required properties:
 - compatible : "mediatek,mt8183_da7219_max98357" for MAX98357A codec
                "mediatek,mt8183_da7219_rt1015" for RT1015 codec
+               "mediatek,mt8183_da7219_rt1015p" for RT1015P codec
 - mediatek,headset-codec: the phandles of da7219 codecs
 - mediatek,platform: the phandle of MT8183 ASoC platform