[ARM] 5373/2: Add gpiolib support to AT91

Add support for gpiolib, including debugfs output, to the AT91 family.
The at91_get/set_gpio_value calls still exist since they are used by the
atmel serial driver.

Signed-off-by: Ryan Mallon <ryan@bluewatersys.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index dbfdf87..5e0c5ab 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -241,6 +241,7 @@
 config ARCH_AT91
 	bool "Atmel AT91"
 	select GENERIC_GPIO
+	select ARCH_REQUIRE_GPIOLIB
 	select HAVE_CLK
 	help
 	  This enables support for systems based on the Atmel AT91RM9200,