ASoC: SOF: ipc4-topology: remove useless assignment

cppcheck warning:

sound/soc/sof/ipc4-topology.c:1533:12: style: Variable 'pipeline' is
assigned a value that is never used. [unreadVariable]
  pipeline = pipe_widget->private;
           ^
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Chao Song <chao.song@intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20220920145405.2089147-3-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/ipc4-topology.c

@@ -1447,7 +1447,6 @@ static int sof_ipc4_control_setup(struct snd_sof_dev *sdev, struct snd_sof_contr
 
 static int sof_ipc4_widget_setup(struct snd_sof_dev *sdev, struct snd_sof_widget *swidget)
 {
-	struct snd_sof_widget *pipe_widget = swidget->pipe_widget;
 	struct sof_ipc4_pipeline *pipeline;
 	struct sof_ipc4_msg *msg;
 	void *ipc_data = NULL;
@@ -1530,7 +1529,7 @@ static int sof_ipc4_widget_setup(struct snd_sof_dev *sdev, struct snd_sof_widget
 				swidget->widget->name);
 			return ret;
 		}
-		pipeline = pipe_widget->private;
+
 		msg->primary &= ~SOF_IPC4_MOD_INSTANCE_MASK;
 		msg->primary |= SOF_IPC4_MOD_INSTANCE(swidget->instance_id);