ASoC: bytcr_rt5640: Use snd_pcm_hw_constraint_single()

Use the new snd_pcm_hw_constraint_single() helper function rather than
installing a list constraint with a single value. Since
snd_pcm_hw_constraint_single() sets a static constraint while
snd_pcm_hw_constraint_list() sets a dynamic constraint the former is
slightly more efficient and it also needs less code.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/soc/intel/boards/bytcr_rt5640.c

@@ -117,20 +117,10 @@ static int byt_codec_fixup(struct snd_soc_pcm_runtime *rtd,
 	return 0;
 }
 
-static unsigned int rates_48000[] = {
-	48000,
-};
-
-static struct snd_pcm_hw_constraint_list constraints_48000 = {
-	.count = ARRAY_SIZE(rates_48000),
-	.list  = rates_48000,
-};
-
 static int byt_aif1_startup(struct snd_pcm_substream *substream)
 {
-	return snd_pcm_hw_constraint_list(substream->runtime, 0,
-			SNDRV_PCM_HW_PARAM_RATE,
-			&constraints_48000);
+	return snd_pcm_hw_constraint_single(substream->runtime,
+			SNDRV_PCM_HW_PARAM_RATE, 48000);
 }
 
 static struct snd_soc_ops byt_aif1_ops = {