dt-bindings: power: avs: qcom,cpr: Convert to DT schema

Convert qcom,cpr.txt to DT schema format.

Signed-off-by: Yassine Oudjana <y.oudjana@protonmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>