The PIN number for Dell headset mode of ALC3271 is wrong.

Fixes: fcc6c877 ("ALSA: hda/realtek - Support Dell headset mode for ALC3271")
Signed-off-by: Shih-Yuan Lee (FourDollars) <sylee@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>