ARM: dts: add syscon compatible string for CP syscon

This syscon needs to be looked up by flash protection, CLCD
display output settings and other consumers.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/boot/dts/integratorcp.dts

@@ -94,7 +94,7 @@ timclk: timclk@1M {
 	};
 
 	syscon {
-		compatible = "arm,integrator-cp-syscon";
+		compatible = "arm,integrator-cp-syscon", "syscon";
 		reg = <0xcb000000 0x100>;
 	};