arm64: dts: mt8173: Add dynamic power node.

This device node is for calculating dynamic power in mW.
Since mt8173 has two clusters, there are two dynamic power
coefficient as well.

Signed-off-by: Dawei Chien <dawei.chien@mediatek.com>
Signed-off-by: Michael.Kao <michael.kao@mediatek.com>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>