ASoC: wm8962: Optimise power consumption for IN4 DC measurement usage

When the hardware is configured with one or both of the IN4 inputs used
for DC measurement (with no DC blocking capacitor connected) then we can
improve power consumption slightly in idle modes by applying a register
write sequence. Provide platform data to enable this, implemented using
a regmap patch.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/include/sound/wm8962.h b/include/sound/wm8962.h
index 1750bed7..79e6d42 100644
--- a/include/sound/wm8962.h
+++ b/include/sound/wm8962.h
@@ -49,6 +49,12 @@
 	bool irq_active_low;
 
 	bool spk_mono;   /* Speaker outputs tied together as mono */
+
+	/**
+	 * This flag should be set if one or both IN4 inputs is wired
+	 * in a DC measurement configuration.
+	 */
+	bool in4_dc_measure;
 };
 
 #endif