ASoC: Implement interrupt driven microphone detection for WM8903

Support use of the WM8903 IRQ for reporting of microphone presence
and short detection.

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

include/sound/wm8903.h

@@ -241,6 +241,8 @@ struct wm8903_platform_data {
 	 */
 	u16 micdet_cfg;
 
+	int micdet_delay;      /* Delay after microphone detection (ms) */
+
 	u32 gpio_cfg[5];       /* Default register values for GPIO pin mux */
 };