powerpc/mpc512x: add MPC5125 reset module support for system restart

Only part of MPC5125 reset module is like as MPC5121.
In detail, RCWH register doesn't contain informations about:
- PCI arbiter
- NAND flash page size
- NAND flash port size

For this reason, in device tree, this module has a different name then
MPC5121 reset module but use the same "struct mpc512x_reset_module"
register definition and the same restart procedure.

Signed-off-by: Matteo Facchinetti <engineering@sirius-es.it>
Signed-off-by: Anatolij Gustschin <agust@denx.de>