ASoC: dt-bindings: mt8192-mt6359: Fix indentation

The items of the 'maintainers' list are indented with three spaces.
Use the usual two spaces instead, for consistency and to silence
yamllint.
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Link: https://lore.kernel.org/r/20210116013403.3490518-1-j.neuschaefer@gmx.netSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/mt8192-mt6359-rt1015-rt5682.yaml

@@ -7,8 +7,8 @@ $schema: http://devicetree.org/meta-schemas/core.yaml#
 title: Mediatek MT8192 with MT6359, RT1015 and RT5682 ASoC sound card driver
 
 maintainers:
-   - Jiaxin Yu <jiaxin.yu@mediatek.com>
-   - Shane Chien <shane.chien@mediatek.com>
+  - Jiaxin Yu <jiaxin.yu@mediatek.com>
+  - Shane Chien <shane.chien@mediatek.com>
 
 description:
   This binding describes the MT8192 sound card.