ARM: dts: vfxxx: Add syscon compatible with OCOTP

Add syscon compatibility with Vybrid OCOTP node. This is required to
access the UID.

Fixes: fa8d20c8 ("ARM: dts: vfxxx: Add node corresponding to OCOTP")
Cc: stable@vger.kernel.org
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Chris Healy <cphealy@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/vfxxx.dtsi

@@ -495,7 +495,7 @@ edma1: dma-controller@40098000 {
 			};
 
 			ocotp: ocotp@400a5000 {
-				compatible = "fsl,vf610-ocotp";
+				compatible = "fsl,vf610-ocotp", "syscon";
 				reg = <0x400a5000 0x1000>;
 				clocks = <&clks VF610_CLK_OCOTP>;
 			};