ALSA: hda - Add a flag to suppress mic auto-switch

Add a new flag spec->suppress_mic_auto_switch for codecs that don't
support unsol events properly like VT1708.

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

sound/pci/hda/hda_generic.c

@@ -3034,6 +3034,9 @@ static int check_auto_mic_availability(struct hda_codec *codec)
 	unsigned int types;
 	int i, num_pins;
 
+	if (spec->suppress_auto_mic)
+		return 0;
+
 	types = 0;
 	num_pins = 0;
 	for (i = 0; i < cfg->num_inputs; i++) {

sound/pci/hda/hda_generic.h

@@ -175,6 +175,7 @@ struct hda_gen_spec {
 	unsigned int automute_speaker_possible:1; /* there are speakers and either LO or HP */
 	unsigned int automute_lo_possible:1;	  /* there are line outs and HP */
 	unsigned int keep_vref_in_automute:1; /* Don't clear VREF in automute */
+	unsigned int suppress_auto_mic:1; /* suppress input jack auto switch */
 	unsigned int line_in_auto_switch:1; /* allow line-in auto switch */
 
 	/* other flags */