Boeffla-Sound: Engine 1.4.7

- reverted some changes supposed to fix the call issues in combination with mic_mode
  and call detection
- mic_mode is now exclusive and not "intelligent" anymore. If you want to make calls,
  switch mic_mode back to default first.
Boeffla-Sound: Engine 1.4.8

- finally completely neutralize mic_mode to avoid any interference to related registers
  when not used (further fix for call issues with certain firmwares)