dt-bindings: power: Add MT8186 power domains

Add power domains dt-bindings for MT8186.

Signed-off-by: Chun-Jie Chen <chun-jie.chen@mediatek.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220215104917.5726-2-chun-jie.chen@mediatek.com
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>