arm64: dts: xilinx: zynqmp: Add RPU subsystem device node

RPU subsystem can be configured in cluster-mode or split mode.
Also each r5 core has separate power domains.

Signed-off-by: Tanmay Shah <tanmay.shah@amd.com>
Acked-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/20221114233940.2096237-3-tanmay.shah@amd.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>