Device-Clean Script for Audio

The audiotool device is cleaned up using the audio_clean program.

This program performs an AUDIO_DRAIN ioctl to flush the device, and then an AUDIO_SETINFO ioctl to reset the device configuration to the default. In addition, this program retrieves the audio chip registers using the AUDIOGETREG ioctl, and any registers deviating from default are reset using AUDIOSETREG ioctl. Because the audio device does not contain any removable media, it does not require an external physical label, and therefore the label is not displayed by the audio_clean script.