ARM: dts: mmp3: Add power domain for the camera

The camera interfaces on MMP3 are on a separate power island that needs
to be turned on for them to operate and, ideally, turned off when the
cameras are not in use.

This hooks the power island with the camera interfaces in the device
tree.

Link: https://lore.kernel.org/r/20200925234805.228251-2-lkundrak@v3.sk


Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>