CRAS: empty_iodev - set functions as static.
CRAS: empty_iodev - set functions as static.

The update_active_node function isn't used outside this file.

BUG=none
TEST=make check

Change-Id: I647df9a9bbec5972349c034eacb563ebf9958367
Signed-off-by: Dylan Reid <c791bfe44996c1eed9c7149a0c5f12a86d58eb85@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/60227

drinkcat/adhd,drinkcat/adhd,drinkcat/adhd,drinkcat/adhd,drinkcat/adhd,drinkcat/adhd