ASoC: dt-bindings: ti,pcm3168a: Convert to json-schema

Convert the Texas Instruments PCM3168A Audio Codec Device Tree binding
documentation to json-schema.

Add missing properties.
Drop unneeded pinctrl properties from example.

Link: https://lore.kernel.org/r/cover.1669980383.git.geert+renesas@glider.be
Link: https://lore.kernel.org/r/87mt7qpylw.wl-kuninori.morimoto.gx@renesas.com


Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/87k01d7rfv.wl-kuninori.morimoto.gx@renesas.com


Signed-off-by: Mark Brown <broonie@kernel.org>