dt-bindings: arm: qcom: document MI01.9 board based on IPQ5332 family

Document the MI01.9 (Reference Design Platform 474) board based on IPQ5332
family of SoCs.

Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Kathiravan T <quic_kathirav@quicinc.com>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230605080531.3879-4-quic_kathirav@quicinc.com