ASoC: es8316: Fix possible NULL pointer deref in es8316_disable_jack_detect()

sound/soc/soc-core.c: soc_remove_component() unconditionally calls
snd_soc_component_set_jack(component, NULL, NULL); on any components
being removed.

This means that on machines where the machine-driver does not provide
a jack through snd_soc_component_set_jack() es8316_disable_jack_detect()
will still get called and at this time es8316->jack will be NULL and
the es8316->jack->status check in es8316_disable_jack_detect() will
lead to a NULL pointer deref.

Fix this by checking for es8316->jack bein NULL at the start of
es8316_disable_jack_detect() and turn the function into a no-op in
that case.

Cc: russianneuromancer <russianneuromancer@ya.ru>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210112101725.44200-1-hdegoede@redhat.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/es8316.c

@@ -681,6 +681,9 @@ static void es8316_disable_jack_detect(struct snd_soc_component *component)
 {
 	struct es8316_priv *es8316 = snd_soc_component_get_drvdata(component);
 
+	if (!es8316->jack)
+		return; /* Already disabled (or never enabled) */
+
 	disable_irq(es8316->irq);
 
 	mutex_lock(&es8316->lock);