dt-bindings: interconnect: Add Qualcomm SM8550

The Qualcomm SM8550 SoC has several bus fabrics that could be
controlled and tuned dynamically according to the bandwidth demand.

Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>