mfd: Move WM831x to generic IRQ

Replace the wm831x-local IRQ infrastructure with genirq, allowing access
to the diagnostic infrastructure of genirq and allowing us to implement
interrupt support for the GPIOs.  The switchover is done within the
wm831x specific IRQ API, further patches will convert the individual
drivers to use genirq directly.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

include/linux/mfd/wm831x/pdata.h

@@ -91,6 +91,7 @@ struct wm831x_pdata {
 	/** Called after subdevices are set up */
 	int (*post_init)(struct wm831x *wm831x);
 
+	int irq_base;
 	int gpio_base;
 	struct wm831x_backlight_pdata *backlight;
 	struct wm831x_backup_pdata *backup;