ASoC: Avoid a redundant read in cs42l51_pdn_event

snd_soc_update_bits already does read-modify-write,
no need to read the register before calling snd_soc_update_bits.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/codecs/cs42l51.c

@@ -175,21 +175,18 @@ static const struct snd_kcontrol_new cs42l51_snd_controls[] = {
 static int cs42l51_pdn_event(struct snd_soc_dapm_widget *w,
 		struct snd_kcontrol *kcontrol, int event)
 {
-	unsigned long value;
-
-	value = snd_soc_read(w->codec, CS42L51_POWER_CTL1);
-	value &= ~CS42L51_POWER_CTL1_PDN;
-
 	switch (event) {
 	case SND_SOC_DAPM_PRE_PMD:
-		value |= CS42L51_POWER_CTL1_PDN;
+		snd_soc_update_bits(w->codec, CS42L51_POWER_CTL1,
+				    CS42L51_POWER_CTL1_PDN,
+				    CS42L51_POWER_CTL1_PDN);
 		break;
 	default:
 	case SND_SOC_DAPM_POST_PMD:
+		snd_soc_update_bits(w->codec, CS42L51_POWER_CTL1,
+				    CS42L51_POWER_CTL1_PDN, 0);
 		break;
 	}
-	snd_soc_update_bits(w->codec, CS42L51_POWER_CTL1,
-		CS42L51_POWER_CTL1_PDN, value);
 
 	return 0;
 }