stm32/sai: no support for PDM interface #4420
Description
Some versions of the SAI peripheral have special support for a hardware block to process PDM data streams. Indeed, in stm32-data, we have sai_vX_Ypdm.yaml register maps. I believe we should add support for properly setting the required registers, ideally while also validating the settings of the SAI sub-block to make sure it is compatible with the one required by the PDM interface.