audio: Fix regressions in adev_open_input_stream

1) Refactor selection logic to select default input if COMPRESS_VOIP
   feature is enabled
2) If stream config allows usb hifi record, proceed to select usecase
   without checking for config again
3) Set channel count requested in open_input_stream for realtime usecases

CRs-Fixed: 2148143
Change-Id: Idb7fc78c6d53578713a79490309d96d9d7980977