ARM: dts: Ux500: move compatible string to chipset

Move the compatible string "stericsson,ab8500" from the board
definitions into the main node in the chipset file where it
belongs.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

arch/arm/boot/dts/ste-href.dtsi

@@ -223,7 +223,6 @@
 		prcmu@80157000 {
 			ab8500 {
 				ab8500-gpio {
-					compatible = "stericsson,ab8500-gpio";
 				};
 
 				ab8500-regulators {