ALSA: jack: don't report input event for phantom jack

There is no input_dev for phantom jack, we should not report
input event for it, otherwise, NULL pointer dereference error
will occur.

Fixes: 2ba2dfa1 ('ALSA: hda - Update to use the new jack kctls method')
Signed-off-by: NJie Yang <yang.jie@intel.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

sound/core/jack.c

@@ -339,6 +339,13 @@ void snd_jack_report(struct snd_jack *jack, int status)
 	if (!jack)
 		return;
 
+	list_for_each_entry(jack_kctl, &jack->kctl_list, list)
+		snd_kctl_jack_report(jack->card, jack_kctl->kctl,
+					    status & jack_kctl->mask_bits);
+
+	if (!jack->input_dev)
+		return;
+
 	for (i = 0; i < ARRAY_SIZE(jack->key); i++) {
 		int testbit = SND_JACK_BTN_0 >> i;
 
@@ -357,10 +364,6 @@ void snd_jack_report(struct snd_jack *jack, int status)
 
 	input_sync(jack->input_dev);
 
-	list_for_each_entry(jack_kctl, &jack->kctl_list, list)
-		snd_kctl_jack_report(jack->card, jack_kctl->kctl,
-					    status & jack_kctl->mask_bits);
-
 }
 EXPORT_SYMBOL(snd_jack_report);