dt-bindings: nvmem: Describe the Amlogic Meson6/Meson8/Meson8b efuse

Amlogic Meson6, Meson8 and Meson8b SoCs have an efuse which contains
calibration data from the factory (for the internal temperature sensor
and some CVBS connector settings). Some manufacturers also store the MAC
address or serial number in the efuse.

This documents the devicetree bindings for the efuse on these SoCs.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>