platform: mellanox: mlx-platform: Add support DGX flavor of next-generation 800GB...

platform: mellanox: mlx-platform: Add support DGX flavor of next-generation 800GB/s ethernet switch.

This system is based on Nvidia SN5600 Spectrum-4 Based 64x800Gb/s ETH
Switch System, with the following key changes:

Key changes:
  1. New system SKU: HI174.
  2. Power Supply: PSU AC replaiced with PDB board (added pdb/pwr
     attributes).
  3. CPLD: Update register map with new PDB related signals.

Signed-off-by: Oleksandr Shamray <oleksandrs@nvidia.com>
Reviewed-by: Vadim Pasternak <vadimp@nvidia.com>
Link: https://patch.msgid.link/20260128075939.2704019-3-oleksandrs@nvidia.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>