ASoC: soc-dai: add common operation to set TDM idle mode

ASoC: soc-dai: add common operation to set TDM idle mode

Some audio devices, like certain Texas Instruments codecs, integrate
configurable bus keepers that dictate the codec's behaviour during
idle TDM slots. Now that we have definitions for various idle modes,
add a snd_soc_dai_set_tdm_idle() operation to control this in a
standardised way.

This is useful on Apple Silicon laptops, where a single I2S bus is
comprised of two physical lines which are ORed just before the
receiving port. When a codec on one line is transmitting, we must
guarantee that the other line is low. We can achieve this by
configuring one codec on each line to use its bus keeper to fill
its line with zeroes during the active slots of the other line.

Signed-off-by: James Calligeros <jcalligeros99@gmail.com>
Link: https://patch.msgid.link/20260301-tdm-idle-slots-v3-5-c6ac5351489a@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>