dt-bindings: clock: Add schema for MSM8909 GCC

The Global Clock Controller (GCC) in the MSM8909 SoC provides clocks,
resets and power domains for the various hardware blocks in the SoC.
Add a DT schema to describe it, similar to other Qualcomm SoCs.

Signed-off-by: Stephan Gerhold <stephan.gerhold@kernkonzept.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220706134132.3623415-2-stephan.gerhold@kernkonzept.com