dt-bindings: arm: qcom: Document the HDK8550 board

dt-bindings: arm: qcom: Document the HDK8550 board

Document the Qualcomm SM8550 based HDK (Hardware Development Kit)
embedded development platform designed by Qualcomm and sold by Lantronix.

[1] https://www.lantronix.com/products/snapdragon-8-gen-2-mobile-hardware-development-kit/

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20240125-topic-sm8550-upstream-hdk8550-v3-1-73bb5ef11cf8@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>