ASoC: core: fix the memory leak in case of remove_aux_dev()

When probing aux_dev, initializing is as below:
device_initialize()
device_add()

So when remove aux_dev, we need do as below:
device_del()
device_put()
Otherwise, the rtd_release() will not be called.

So here using device_unregister() to replace device_del(),
like the action in soc_remove_link_dais().
Signed-off-by: Nliu chuansheng <chuansheng.liu@intel.com>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/soc-core.c

@@ -1556,7 +1556,7 @@ static void soc_remove_aux_dev(struct snd_soc_card *card, int num)
 	/* unregister the rtd device */
 	if (rtd->dev_registered) {
 		device_remove_file(rtd->dev, &dev_attr_codec_reg);
-		device_del(rtd->dev);
+		device_unregister(rtd->dev);
 		rtd->dev_registered = 0;
 	}