ASoC: Explicitly clear WM8993 ramp controls on power down

This helps ensure that the ramp logic is reset when powering back up.

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

sound/soc/codecs/wm8993.c

@@ -1030,6 +1030,12 @@ static int wm8993_set_bias_level(struct snd_soc_codec *codec,
 				    WM8993_VMID_SEL_MASK | WM8993_BIAS_ENA,
 				    0);
 
+		snd_soc_update_bits(codec, WM8993_ANTIPOP2,
+				    WM8993_STARTUP_BIAS_ENA |
+				    WM8993_VMID_BUF_ENA |
+				    WM8993_VMID_RAMP_MASK |
+				    WM8993_BIAS_SRC, 0);
+
 #ifdef CONFIG_REGULATOR
                /* Post 2.6.34 we will be able to get a callback when
                 * the regulators are disabled which we can use but