targets/audio: Pack the structures
targets/audio: Pack the structures

Mirrors https://chromium-review.googlesource.com/c/chromiumos/third_party/adhd/+/1779774 .

Fixes #4119.

dnschneid/crouton,dnschneid/crouton,dnschneid/crouton,dnschneid/crouton,dnschneid/crouton,dnschneid/crouton