ALSA: hda/realtek - Add unplug function into unplug state of Headset Mode for ALC225

Forgot to add unplug function to unplug state of headset mode
for ALC225.

Signed-off-by: Kailang Yang <kailang@realtek.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>