dt-bindings: clock: provide separate bindings for qcom,gcc-mdm9615

The global clock controller on MDM9615 uses external CXO and PLL7
clocks. Split the qcom,gcc-mdm9615 to the separate schema file.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20230512211727.3445575-4-dmitry.baryshkov@linaro.org


Signed-off-by: Bjorn Andersson <andersson@kernel.org>