gpiolib: cleanup chained handler and data

Clean up chained handler and handler data if they were set by
gpiochip_set_chained_irqchip().

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index 2c1e639..96a6788 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -121,6 +121,7 @@
 	unsigned int		irq_base;
 	irq_flow_handler_t	irq_handler;
 	unsigned int		irq_default_type;
+	int			irq_parent;
 #endif
 
 #if defined(CONFIG_OF_GPIO)