dt-bindings: phy: qcom,snps-eusb2: document the SM8650 Synopsys eUSB2 PHY

Document the Synopsys eUSB2 PHY on the SM8650 Platform by using
the SM8550 as fallback.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20231030-topic-sm8650-upstream-phy-v2-4-a543a4c4b491@linaro.org


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