ASoC: add for_each_dpcm_fe() macro

To be more readable code, this patch adds
new for_each_dpcm_fe() macro, and replace existing code to it.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/include/sound/soc-dpcm.h b/include/sound/soc-dpcm.h
index 9bb92f1..f130de6 100644
--- a/include/sound/soc-dpcm.h
+++ b/include/sound/soc-dpcm.h
@@ -103,6 +103,9 @@ struct snd_soc_dpcm_runtime {
 	int trigger_pending; /* trigger cmd + 1 if pending, 0 if not */
 };
 
+#define for_each_dpcm_fe(be, stream, dpcm)				\
+	list_for_each_entry(dpcm, &(be)->dpcm[stream].fe_clients, list_fe)
+
 /* can this BE stop and free */
 int snd_soc_dpcm_can_be_free_stop(struct snd_soc_pcm_runtime *fe,
 		struct snd_soc_pcm_runtime *be, int stream);