ASoC: dt-bindings: mediatek: mt8192: Add i2s-share properties

The Mediatek AFE PCM controller for MT8192 allows sharing of an I2S bus
between two busses. Add a pattern for these properties in the
dt-binding.

Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Link: https://lore.kernel.org/r/20220429203039.2207848-2-nfraprado@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>