ALSA: hda - Add mute LED pin quirk for HP 15 touchsmart

This makes the mute LED work on a HP 15 touchsmart machine.

BugLink: https://bugs.launchpad.net/bugs/1334950


Signed-off-by: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>