dt-bindings: cpufreq: cpufreq-qcom-hw: Convert to YAML bindings

Convert Qualcomm cpufreq devicetree binding to YAML.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>