dt-bindings: interrupt-controller: qcom,pdc: document qcom,qdu1000-pdc

Add QDU1000 PDC, already used in upstreamed DTS.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230416102831.105136-1-krzysztof.kozlowski@linaro.org


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