ASoC: SOF: sof-audio: remove useless assignment

There is no need to assign spcm to NULL. Removing this assignment also
removes a false alarm reported by cppcheck.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Link: https://lore.kernel.org/r/20220421162600.302230-1-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/sof-audio.h

@@ -404,8 +404,7 @@ struct snd_sof_pcm *snd_sof_find_spcm_dai(struct snd_soc_component *scomp,
 					  struct snd_soc_pcm_runtime *rtd)
 {
 	struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(scomp);
-
-	struct snd_sof_pcm *spcm = NULL;
+	struct snd_sof_pcm *spcm;
 
 	list_for_each_entry(spcm, &sdev->pcm_list, list) {
 		if (le32_to_cpu(spcm->pcm.dai_id) == rtd->dai_link->id)