ASoC: Convert WM8903 bias management to use snd_soc_update_bits()

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>

sound/soc/codecs/wm8903.c

@@ -1139,15 +1139,13 @@ static int wm8903_add_widgets(struct snd_soc_codec *codec)
 static int wm8903_set_bias_level(struct snd_soc_codec *codec,
 				 enum snd_soc_bias_level level)
 {
-	u16 reg;
-
 	switch (level) {
 	case SND_SOC_BIAS_ON:
+		break;
 	case SND_SOC_BIAS_PREPARE:
-		reg = snd_soc_read(codec, WM8903_VMID_CONTROL_0);
-		reg &= ~(WM8903_VMID_RES_MASK);
-		reg |= WM8903_VMID_RES_50K;
-		snd_soc_write(codec, WM8903_VMID_CONTROL_0, reg);
+		snd_soc_update_bits(codec, WM8903_VMID_CONTROL_0,
+				    WM8903_VMID_RES_MASK,
+				    WM8903_VMID_RES_50K);
 		break;
 
 	case SND_SOC_BIAS_STANDBY:
@@ -1174,10 +1172,9 @@ static int wm8903_set_bias_level(struct snd_soc_codec *codec,
 					    WM8903_CP_DYN_V);
 		}
 
-		reg = snd_soc_read(codec, WM8903_VMID_CONTROL_0);
-		reg &= ~(WM8903_VMID_RES_MASK);
-		reg |= WM8903_VMID_RES_250K;
-		snd_soc_write(codec, WM8903_VMID_CONTROL_0, reg);
+		snd_soc_update_bits(codec, WM8903_VMID_CONTROL_0,
+				    WM8903_VMID_RES_MASK,
+				    WM8903_VMID_RES_250K);
 		break;
 
 	case SND_SOC_BIAS_OFF: