dt-bindings: clock: qcom,spmi-clkdiv: convert to DT schema

Convert Qualcomm SPMI PMIC clock divider bindings to DT schema.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221223111835.37610-1-krzysztof.kozlowski@linaro.org