The HAL to be used listed in the json file 
/usr/agl-service-audio-4a/ahl-agl-service-audio-4a-config.json

BUT all hal present in the 4a hal directory are loaded
/usr/agl-service-audio-4a/ahl-agl-service-audio-4a-config.json

This creates :

 - systematic error in some cases (e.g. some intel config)
 - slow down the boot process
 - can induce errors on non tested, non needed configurations

4a should only load the hal which are listed in the json file.