sound: Retire feedertab_entry

[christos]

Summary

Have an SLIST of feeder_class directly. This way we simplify the code,
and also avoid the additional malloc()/free() for each entry.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week

[markj]

sys/dev/sound/pcm/feeder.c

44

How is this list locked?

71

This loop can be replaced by SLIST_INIT(&feedertab);

[christos]

Address Mark's comment.

[christos]

sys/dev/sound/pcm/feeder.c

44

It isn't. This list is created once after sound.ko has been loaded, and destroyed on unload. There is no adding/removing in the meantime.