dt-bindings: memory: convert Synopsys IntelliDDR memory controller to dtschema

dt-bindings: memory: convert Synopsys IntelliDDR memory controller to dtschema

Convert Synopsys IntelliDDR Multi Protocol memory controller (present in
Xilinx Zynq and ZynqMP) bindings to DT schema format using json-schema.

New binding contains copied parts of description from previous binding
document, therefore the license is set as GPL-2.0-only.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20210818113139.84869-1-krzysztof.kozlowski@canonical.com
Signed-off-by: Rob Herring <robh@kernel.org>