ASoC: soc-dpcm: tidyup for_each_dpcm_xx() macro

for_each_dpcm_xx() macro is using "dpcm" as parameter (1),
but, it is also struct member (2).

	#define for_each_dpcm_fe(be, stream, dpcm) \
	list_for_each_entry(dpcm, &(be)->dpcm[stream]...)
	                    ^^^^(1)      ^^^^(2)

Thus, it will be compile error if user not used "dpcm" as parameter

	for_each_dpcm_fe(be, stream, dp)
	                             ^^
This patch fixup it.

Reported-by: Pavel Machek <pavel@denx.de>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87tv7x7idx.wl-kuninori.morimoto.gx@renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>

include/sound/soc-dpcm.h

@@ -103,15 +103,15 @@ 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)
+#define for_each_dpcm_fe(be, stream, _dpcm)				\
+	list_for_each_entry(_dpcm, &(be)->dpcm[stream].fe_clients, list_fe)
 
-#define for_each_dpcm_be(fe, stream, dpcm)				\
-	list_for_each_entry(dpcm, &(fe)->dpcm[stream].be_clients, list_be)
-#define for_each_dpcm_be_safe(fe, stream, dpcm, _dpcm)			\
-	list_for_each_entry_safe(dpcm, _dpcm, &(fe)->dpcm[stream].be_clients, list_be)
-#define for_each_dpcm_be_rollback(fe, stream, dpcm)			\
-	list_for_each_entry_continue_reverse(dpcm, &(fe)->dpcm[stream].be_clients, list_be)
+#define for_each_dpcm_be(fe, stream, _dpcm)				\
+	list_for_each_entry(_dpcm, &(fe)->dpcm[stream].be_clients, list_be)
+#define for_each_dpcm_be_safe(fe, stream, _dpcm, __dpcm)			\
+	list_for_each_entry_safe(_dpcm, __dpcm, &(fe)->dpcm[stream].be_clients, list_be)
+#define for_each_dpcm_be_rollback(fe, stream, _dpcm)			\
+	list_for_each_entry_continue_reverse(_dpcm, &(fe)->dpcm[stream].be_clients, list_be)
 
 /* can this BE stop and free */
 int snd_soc_dpcm_can_be_free_stop(struct snd_soc_pcm_runtime *fe,