dt-bindings: clock: add SM6350 QCOM Graphics clock bindings

Add device tree bindings for graphics clock controller for
Qualcomm Technology Inc's SM6350 SoCs.

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
Signed-off-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220222011534.3502-3-konrad.dybcio@somainline.org