soc: mediatek: pm-domains: Add default power off flag

For some power domain, like conn on MT8192, it should be default OFF.
Because the power on/off control relies the function of connectivity chip
and its firmware. And if project choose other chip vendor solution,
those necessary connectivity functions will not provided.

Signed-off-by: Weiyi Lu <weiyi.lu@mediatek.com>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Link: https://lore.kernel.org/r/20201030113622.201188-16-enric.balletbo@collabora.com


Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>