ALSA: pcm_dmaengine: Use pcm_for_each_format() macro for PCM format iteration

The new macro can fix the sparse warnings gracefully:
  sound/core/pcm_dmaengine.c:429:50: warning: restricted snd_pcm_format_t degrades to integer
  sound/core/pcm_dmaengine.c:429:55: warning: restricted snd_pcm_format_t degrades to integer
  sound/core/pcm_dmaengine.c:429:79: warning: restricted snd_pcm_format_t degrades to integer

No functional changes, just sparse warning fixes.

Link: https://lore.kernel.org/r/20200206163945.6797-8-tiwai@suse.deSigned-off-by: NTakashi Iwai <tiwai@suse.de>

sound/core/pcm_dmaengine.c

@@ -426,7 +426,7 @@ int snd_dmaengine_pcm_refine_runtime_hwparams(
 		 * default assumption is that it supports 1, 2 and 4 bytes
 		 * widths.
 		 */
-		for (i = SNDRV_PCM_FORMAT_FIRST; i <= SNDRV_PCM_FORMAT_LAST; i++) {
+		pcm_for_each_format(i) {
 			int bits = snd_pcm_format_physical_width(i);
 
 			/*