ASoC: intel: bytcr_rt5651: add null check to support_button_press

When removing sof module the support_button_press function will oops
because hp_jack pointer is not checked for NULL. So add a check to fix
this.
Signed-off-by: NJaska Uimonen <jaska.uimonen@intel.com>
Signed-off-by: NPierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20190927201408.925-2-pierre-louis.bossart@linux.intel.comSigned-off-by: NMark Brown <broonie@kernel.org>

sound/soc/codecs/rt5651.c

@@ -1770,6 +1770,9 @@ static int rt5651_detect_headset(struct snd_soc_component *component)
 
 static bool rt5651_support_button_press(struct rt5651_priv *rt5651)
 {
+	if (!rt5651->hp_jack)
+		return false;
+
 	/* Button press support only works with internal jack-detection */
 	return (rt5651->hp_jack->status & SND_JACK_MICROPHONE) &&
 		rt5651->gpiod_hp_det == NULL;