ASoC: fsl_sai: Add PDM daifmt support

PDM format is used for 1-bit stream, so clear the FBT and SYWD,
and the each dataline only has one channel data.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Link: https://lore.kernel.org/r/1655451877-16382-2-git-send-email-shengjiu.wang@nxp.com


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