ASoC: dt-bindings: mt6359: Update generic node name and dmic-mode

Some fix and updates in the following items:
1. examples:
Update generic node name to 'audio-codec' to comply with the
coming change in 'mt6359.dtsi'. This change is necessary to fix the
dtbs_check error:
pmic: 'mt6359codec' does not match any of the regexes: 'pinctrl-[0-9]+'

2. mediatek,dmic-mode:
After inspecting the .dts and .dtsi files using 'mt6359-codec', it was
discovered that the definitions of 'two wires' and 'one wire' are
inverted compared to the DT schema.
For example, the following boards using MT6359 PMIC:
- mt8192-asurada.dtsi
- mt8195-cherry.dtsi
These boards use the same definitions of 'dmic-mode' as other boards
using MT6358 PMIC. The meaning of '0' or '1' has been noted as comments
in the device trees.

Upon examining the code in [1] and [2], it was confirmed that the
definitions of 'dmic-mode' are consistent between "MT6359 PMIC" and
"MT6358 PMIC". Therefore, the DT Schema should be correct as is.

References:
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/sound/soc/codecs/mt6358.c#n1875
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/sound/soc/codecs/mt6359.c#L1515

Fixes: 539237d1c609 ("dt-bindings: mediatek: mt6359: add codec document")
Signed-off-by: Jiaxin Yu <jiaxin.yu@mediatek.com>
Signed-off-by: Macpaul Lin <macpaul.lin@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://patch.msgid.link/20240930075451.14196-1-macpaul.lin@mediatek.com
Signed-off-by: Mark Brown <broonie@kernel.org>