Add an appropriate "#power-domain-cells" property to the cpg_clocks
device node, to create the CPG/MSTP Clock Domain.
Add "power-domains" properties to all device nodes for devices that are
part of the CPG/MSTP Clock Domain and can be power-managed through an
MSTP clock. This applies to most on-SoC devices, which have a
one-to-one mapping from SoC device to DT device node. A notable
exception is the "sound" node, which represents multiple SoC devices,
each having their own MSTP clocks.