gpiolib: Hook up WM8994 gpio_to_irq()

Not sure where this went.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/gpio/wm8994-gpio.c

@@ -140,6 +140,7 @@ static struct gpio_chip template_chip = {
 	.get			= wm8994_gpio_get,
 	.direction_output	= wm8994_gpio_direction_out,
 	.set			= wm8994_gpio_set,
+	.to_irq			= wm8994_gpio_to_irq,
 	.dbg_show		= wm8994_gpio_dbg_show,
 	.can_sleep		= 1,
 };