ASoC: wm_hubs: Push check for idle_bias_off out into drivers

For later wm_hubs devices we have much less need to keep the biases up
even when using single ended line outputs so flag idle_bias_off for
everything except the WM8993 and WM8994.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/sound/soc/codecs/wm8994.c b/sound/soc/codecs/wm8994.c
index 11ca19b..c262918 100644
--- a/sound/soc/codecs/wm8994.c
+++ b/sound/soc/codecs/wm8994.c
@@ -3396,10 +3396,18 @@
 	pm_runtime_enable(codec->dev);
 	pm_runtime_resume(codec->dev);
 
+	/* By default use idle_bias_off, will override for WM8994 */
+	codec->dapm.idle_bias_off = 1;
+
 	/* Set revision-specific configuration */
 	wm8994->revision = snd_soc_read(codec, WM8994_CHIP_REVISION);
 	switch (control->type) {
 	case WM8994:
+		/* Single ended line outputs should have VMID on. */
+		if (!wm8994->pdata->lineout1_diff ||
+		    !wm8994->pdata->lineout2_diff)
+			codec->dapm.idle_bias_off = 0;
+
 		switch (wm8994->revision) {
 		case 2:
 		case 3: