dt-bindings: imx-ocotp: Add i.MX8MM compatible

Add compatible for i.MX8MM as per arch/arm64/boot/dts/freescale/imx8mm.dtsi

Signed-off-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Cc: Rob Herring <robh@kernel.org>
Reviewed-by: Leonard Crestez <leonard.crestez@nxp.com>
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

@@ -15,6 +15,7 @@ Required properties:
  "fsl,imx6sll-ocotp" (i.MX6SLL),
  "fsl,imx7ulp-ocotp" (i.MX7ULP),
  "fsl,imx8mq-ocotp" (i.MX8MQ),
+ "fsl,imx8mm-ocotp" (i.MX8MM),
  followed by "syscon".
 - #address-cells : Should be 1
 - #size-cells : Should be 1