dt-bindings: interconnect: Add Qualcomm SC7180 DT bindings

The Qualcomm SC7180 platform has several bus fabrics that could be
controlled and tuned dynamically according to the bandwidth demand.

Signed-off-by: Odelu Kukatla <okukatla@codeaurora.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/1583241493-21212-2-git-send-email-okukatla@codeaurora.org
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>