pinctrl/at91: convert driver to use gpiolib irqchip

This converts the AT91 pin control driver to register its
chained irq handler and irqchip using the helpers in the
gpiolib core.

Signed-off-by: Alexander Stein <alexanders83@web.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig
index fbd7eda..8b6597c 100644
--- a/drivers/pinctrl/Kconfig
+++ b/drivers/pinctrl/Kconfig
@@ -84,6 +84,9 @@
 	depends on ARCH_AT91
 	select PINMUX
 	select PINCONF
+	select GPIOLIB
+	select OF_GPIO
+	select GPIOLIB_IRQCHIP
 	help
 	  Say Y here to enable the at91 pinctrl driver