hw/mips/cps: create CPC block inside CPS

hw/mips/cps: create CPC block inside CPS

Create Cluster Power Controller and add a link to the CPC MemoryRegion
in GCR. Guest can enable / map CPC to any physical address by writing to
the memory-mapped GCR_CPC_BASE register.

Set vp-start-reset property to 1 to allow only first VP to run from reset.
Others are brought up by the guest via CPC memory-mapped registers.

Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>