commit 392c9da2 upstream.

We have two new Dell laptop models, they have the same ALC255 pin
definition, but not in the pin quirk table yet, as a result, the
headset microphone can't work. After adding the definition in the
table, the headset microphone works well.
Signed-off-by: Hui Wang <hui.wang@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>