Otherwise, the mute led can't work at all.
Tested-by: NTaihsiang Ho <taihsiang.ho@canonical.com>
Cc: <stable@vger.kernel.org>
BugLink: https://bugs.launchpad.net/bugs/1410704Signed-off-by: NHui Wang <hui.wang@canonical.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>