xilinx: Move IPI functions to common file

pm_service ipi functions can be used by other xilinx
platforms. So move it to common directory. Also change
node_id member type in pm_proc structure so it can be
used for versal where device IDs are used instead of
node IDs.

To accommodate this change header files are re-organized.

Signed-off-by: Tejas Patel <tejas.patel@xilinx.com>
Reviewed-by: Siva Durga Prasad Paladugu <siva.durga.paladugu@xilinx.com>
Signed-off-by: Jolly Shah <jollys@xilinx.com>