dt-bindings: clock: Make marvell,mmp2-clock a power controller

This is a binding for the MMP2 power management units. As such apart from
providing the clocks, they also manage the power islands.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Link: https://lkml.kernel.org/r/20200519224151.2074597-10-lkundrak@v3.sk


Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>