ALSA: hda/conexant - Add hp-mic-fix model string

Add "hp-mic-fix" model string for Conexant codecs so that user can
test the quirk without recompiling.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

Documentation/sound/hd-audio/models.rst

@@ -263,6 +263,8 @@ hp-dock
     HP dock support
 mute-led-gpio
     Mute LED control via GPIO
+hp-mic-fix
+    Fix for headset mic pin on HP boxes
 
 STAC9200
 ========

sound/pci/hda/patch_conexant.c

@@ -998,6 +998,7 @@ static const struct hda_model_fixup cxt5066_fixup_models[] = {
 	{ .id = CXT_FIXUP_MUTE_LED_EAPD, .name = "mute-led-eapd" },
 	{ .id = CXT_FIXUP_HP_DOCK, .name = "hp-dock" },
 	{ .id = CXT_FIXUP_MUTE_LED_GPIO, .name = "mute-led-gpio" },
+	{ .id = CXT_FIXUP_HP_MIC_NO_PRESENCE, .name = "hp-mic-fix" },
 	{}
 };