arm64: dts: mediatek: add mt2712 cpufreq related device nodes

Add opp v2 information,
and also add clocks, regulators and opp information into cpu nodes

Signed-off-by: Andrew-sh Cheng <andrew-sh.cheng@mediatek.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>