dt-bindings: arm: socionext: add Synquacer platforms

Socionext's DeveloperBox is based on the SC2A11B SoC (Synquacer).
Specify bindings for the platform and boards based on that.

Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
Link: https://lore.kernel.org/r/20230621153658.60646-1-jaswinder.singh@linaro.org


Signed-off-by: Rob Herring <robh@kernel.org>