dt-bindings: nvmem: Add bindings doc for Sunplus OCOTP driver

Add bindings doc for Sunplus OCOTP driver

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Vincent Shih <vincent.sunplus@gmail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20220223223502.29454-4-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>