[ARM] realview: add PL061 gpiolib support

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index e4971e4..0dd29eb 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -217,6 +217,7 @@
 	select ICST307
 	select GENERIC_TIME
 	select GENERIC_CLOCKEVENTS
+	select ARCH_WANT_OPTIONAL_GPIOLIB
 	help
 	  This enables support for ARM Ltd RealView boards.