dt-bindings: clock: split qcom,gcc-msm8974,-msm8226 to the separate file

Move schema for the GCC on MSM8974 and MSM8226 platforms to a separate
file to be able to define device-specific clock properties.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221204124508.1415713-2-dmitry.baryshkov@linaro.org