ASoC: Jack: Fix NULL pointer dereference in snd_soc_jack_report

Check for existance of jack before tracing.
NULL pointer dereference has been reported by KASAN while unloading
machine driver (snd_soc_cnl_rt274).

Signed-off-by: Pawel Harlozinski <pawel.harlozinski@linux.intel.com>
Link: https://lore.kernel.org/r/20191112130237.10141-1-pawel.harlozinski@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

sound/soc/soc-jack.c

@@ -82,10 +82,9 @@ void snd_soc_jack_report(struct snd_soc_jack *jack, int status, int mask)
 	unsigned int sync = 0;
 	int enable;
 
-	trace_snd_soc_jack_report(jack, mask, status);
-
 	if (!jack)
 		return;
+	trace_snd_soc_jack_report(jack, mask, status);
 
 	dapm = &jack->card->dapm;