sof-soundwire: cleanups for codecs with multiple functions

alsa-project/alsa-ucm-conf pull request #775 was edited from perexg:

The load mechanism assumed only one multi-codec in the system, but
    we saw in #774 multiple instances of those codecs (rt1320 and rt713).
    
    Make the load mechanism straight:
    
    - introduce file variables
    - remove shadow variables
    - probe multi-codecs separately and modify the file variables
    - test for duplicate file inclusion (in both sof-soundwire / HiFi configs)
    - merge dmic configs for rt712,rt713 to one file
    
    This change also removes filters for speaker/headset/mic init includes.
    The file variables + multi-codec probe replaces this functionality and
    if the driver reports an "unknown" codec, UCM config should be updated anyway.


Link: https://github.com/alsa-project/alsa-ucm-conf/issues/774

Request URL   : https://github.com/alsa-project/alsa-ucm-conf/pull/775
Patch URL     : https://github.com/alsa-project/alsa-ucm-conf/pull/775.patch
Repository URL: https://github.com/alsa-project/alsa-ucm-conf