Device-Clean Script for Audio

The audio device is cleaned up with an audio-clean script. The script performs an AUDIO_DRAIN ioctl system call to flush the device, then an AUDIO_SETINFO ioctl system call to reset the device configuration to default. In addition, the script retrieves the audio chip registers using the AUDIOGETREG ioctl system call. Any registers deviating from default are reset using the AUDIOSETREG ioctl system call.