ALSA: Handle NULL jacks in snd_jack_report()

Facilitate drivers that wish to carry on if they can't create a jack
input device by handling attempts to report the state of a NULL jack,
removing the need to check for initialisation before use.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/jack.c

@@ -147,6 +147,9 @@ EXPORT_SYMBOL(snd_jack_set_parent);
  */
 void snd_jack_report(struct snd_jack *jack, int status)
 {
+	if (!jack)
+		return;
+
 	if (jack->type & SND_JACK_HEADPHONE)
 		input_report_switch(jack->input_dev, SW_HEADPHONE_INSERT,
 				    status & SND_JACK_HEADPHONE);