ALSA: hda/realtek - Disable headset Mic VREF for headset mode of ALC225

ALSA: hda/realtek - Disable headset Mic VREF for headset mode of ALC225

BugLink: https://launchpad.net/bugs/1821290
Disable Headset Mic VREF for headset mode of ALC225.
This will be controlled by coef bits of headset mode functions.

[ Fixed a compile warning and code simplification -- tiwai ]

Signed-off-by: Kailang Yang <kailang@realtek.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
(backported from commit d1dd42110d2727e81b9265841a62bc84c454c3a2)
Signed-off-by: Wen-chien Jesse Sung <jesse.sung@canonical.com>
Acked-by: AceLan Kao <acelan.kao@canonical.com>
Acked-by: hwang4 <hui.wang@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>