dt-bindings: cpufreq: qcom-cpufreq-nvmem: specify supported opp tables

Add additional info on what opp tables the defined devices in this schema
supports (operating-points-v2-kryo-cpu and operating-points-v2-qcom-level)
and reference them.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>