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 improves filters for speaker/headset/mic init includes.

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