dt-bindings: nvmem: imx-ocotp: add compatible string for i.MX7ULP

Add new compatible string for i.MX7ULP SOC.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/nvmem/imx-ocotp.txt

@@ -11,6 +11,7 @@ Required properties:
 	"fsl,imx6ul-ocotp" (i.MX6UL),
 	"fsl,imx7d-ocotp" (i.MX7D/S),
 	"fsl,imx6sll-ocotp" (i.MX6SLL),
+	"fsl,imx7ulp-ocotp" (i.MX7ULP),
 	followed by "syscon".
 - #address-cells : Should be 1
 - #size-cells : Should be 1