ARM: ux500: Provide a AB8500 GPIO Device Tree node

Here we're adding a node for the AB8500 GPIO device. This will allow
other DT:ed components to obtain GPIOs for use within their drivers.
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>

arch/arm/boot/dts/dbx5x0.dtsi

@@ -326,6 +326,11 @@
 				interrupt-controller;
 				#interrupt-cells = <2>;
 
+				ab8500_gpio: ab8500-gpio {
+					gpio-controller;
+					#gpio-cells = <2>;
+				};
+
 				ab8500-rtc {
 					compatible = "stericsson,ab8500-rtc";
 					interrupts = <17 0x4