arm64: dts: st: add power domain on stm32mp25

Add power domains on STM32MP25x SoC for supported low power modes:
- CPU_PD0/1: domain for idle of each core Cortex A35 (CStop)
- CLUSTER_PD: D1 domain with Stop1 and LP-Stop1 modes support when
  the Cortex A35 cluster and each device assigned to CPU1=CA35
  are deactivated
- RET_PD: D1 domain retention (VDDCore is reduced) to support
          the LPLV-Stop1 mode

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>