Otherwise, the pin will be regarded as microphone, and the jack name
is "Mic Phantom", it is always on in the pulseaudio even nothing is
plugged into the jack. So the UI is confusing to users since the
microphone always shows up in the UI even there is no microphone
plugged.

After adding this flag, the jack name is "Headset Mic Phantom", then
the pulseaudio can handle its detection correctly.

Fixes: f0ba9d69 ("ALSA: hda/realtek - Fix Dell headset Mic can't record")
Cc: <stable@vger.kernel.org>
Signed-off-by: Hui Wang <hui.wang@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>