The mute LED should be automatically turned on/off based
on the audio-card's mixer settings.
Add the standardized default-trigger name for this, so that the alsa
code can turn the LED on/off as appropriate (on supported audio cards).
Reviewed-by: Marek BehĂșn <kabel@kernel.org> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>