catpt: Switch to use list_entry_is_head() helper

Since we got list_entry_is_head() helper in the generic header,
we may switch catpt to use it. It removes the need in additional variable.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lore.kernel.org/r/20201214172138.44267-1-andriy.shevchenko@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/catpt/pcm.c

@@ -331,7 +331,7 @@ static int catpt_dai_apply_usettings(struct snd_soc_dai *dai,
 {
 	struct catpt_dev *cdev = dev_get_drvdata(dai->dev);
 	struct snd_soc_component *component = dai->component;
-	struct snd_kcontrol *pos, *kctl = NULL;
+	struct snd_kcontrol *pos;
 	const char *name;
 	int ret;
 	u32 id = stream->info.stream_hw_id;
@@ -356,17 +356,15 @@ static int catpt_dai_apply_usettings(struct snd_soc_dai *dai,
 
 	list_for_each_entry(pos, &component->card->snd_card->controls, list) {
 		if (pos->private_data == component &&
-		    !strncmp(name, pos->id.name, sizeof(pos->id.name))) {
-			kctl = pos;
+		    !strncmp(name, pos->id.name, sizeof(pos->id.name)))
 			break;
-		}
 	}
-	if (!kctl)
+	if (list_entry_is_head(pos, &component->card->snd_card->controls, list))
 		return -ENOENT;
 
 	if (stream->template->type != CATPT_STRM_TYPE_LOOPBACK)
-		return catpt_set_dspvol(cdev, id, (long *)kctl->private_value);
-	ret = catpt_ipc_mute_loopback(cdev, id, *(bool *)kctl->private_value);
+		return catpt_set_dspvol(cdev, id, (long *)pos->private_value);
+	ret = catpt_ipc_mute_loopback(cdev, id, *(bool *)pos->private_value);
 	if (ret)
 		return CATPT_IPC_ERROR(ret);
 	return 0;