dt-bindings: clk: qcom: gcc-sm6115: Document SM6115 GCC

Add device tree bindings for global clock controller on SM6115 and
SM4250 SoCs (pin and software compatible).

Signed-off-by: Iskren Chernev <iskren.chernev@gmail.com>
Link: https://lore.kernel.org/r/20210805161107.1194521-2-iskren.chernev@gmail.com


Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>