dt-bindings: clock: Add MDM9607 GCC clock bindings

Add device tree bindings for global clock controller on MDM9607 SoC.

Signed-off-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Link: https://lore.kernel.org/r/20210313020310.386152-1-konrad.dybcio@somainline.org
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>