ALSA: hda/realtek - Fix Dell AIO LineOut issue

Dell AIO had LineOut jack.
Add LineOut verb into this patch.

[ Additional notes:
  the ALC274 codec seems requiring the fixed pin / DAC connections for
  HP / line-out pins for enabling EQ for speakers; i.e. the HP / LO
  pins expect to be connected with NID 0x03 while keeping the speaker
  with NID 0x02.  However, by adding a new line-out pin, the
  auto-parser assigns the NID 0x02 for HP/LO pins as primary outputs.
  As an easy workaround, we provide the preferred_pairs[] to map
  forcibly for these pins. -- tiwai ]

Fixes: 75ee94b2

 ("ALSA: hda - fix headset mic problem for Dell machines with alc274")
Signed-off-by: Kailang Yang <kailang@realtek.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>