dt-bindings: phy: qcom,sc8280xp-qmp-ufs-phy: document the SM8650 QMP UFS PHY

Document the QMP UFS PHY on the SM8650 Platform.

Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20231030-topic-sm8650-upstream-phy-v2-1-a543a4c4b491@linaro.org


Signed-off-by: Vinod Koul <vkoul@kernel.org>