ARM: mxs: get ocotp base address from device tree

Instead of using the static definitions, get ocotp base address from
device tree with mapping.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

arch/arm/boot/dts/imx23.dtsi

@@ -322,6 +322,7 @@
 			};
 
 			ocotp@8002c000 {
+				compatible = "fsl,ocotp";
 				reg = <0x8002c000 0x2000>;
 				status = "disabled";
 			};