dt-bindings: arm: Convert ZTE board/soc bindings to json-schema

Convert ZTE SoC bindings to DT schema format using json-schema.

Cc: Jun Nie <jun.nie@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: devicetree@vger.kernel.org
Acked-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>