dt-bindings: i2c: mv64xxx: Add compatible for the A100 i2c node.

Allwinner A100 have a mv64xxx i2c interface available to be used.

Signed-off-by: Yangtao Li <frank@allwinnertech.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>