ALSA: hda - Add docking station support for Lenovo Thinkpad T420s

Lenovo Thinkpad T420s uses the same codec as T420, so apply the
same quirk to enable audio output on a docking station.

Signed-off-by: Peter Große <pegro@friiks.de>
Link: https://lore.kernel.org/r/20200122180106.9351-1-pegro@friiks.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>