dt-bindings: i3c: Convert snps,dw-i3c-master to DT schema

Convert the Synopsys Designware I3C master to DT schema format.

Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220422192236.2594577-1-robh@kernel.org