ARM: ux500: Add db8500 Device Tree node for ab8500-sysctrl

This adds the DT node for the mfd/ab8500-sysctrl driver. It will
allow probing of the driver during a Device Tree enabled boot.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

arch/arm/boot/dts/db8500.dtsi

@@ -328,6 +328,10 @@ ab8500-ponkey {
 					interrupt-names = "ONKEY_DBF", "ONKEY_DBR";
 				};
 
+				ab8500-sysctrl {
+					compatible = "stericsson,ab8500-sysctrl";
+				};
+
 				ab8500-regulators {
 					compatible = "stericsson,ab8500-regulator";