nvl32: get through enumerating all devices

Adds support for enumerating devices through
entity-manager

Tested by:
putting on nvl32-obmc and booting bmc, all devices
are enumerated:
```
root@nvl32-obmc:~# busctl tree xyz.openbmc_project.EntityManager
`- /xyz
  `- /xyz/openbmc_project
    |- /xyz/openbmc_project/EntityManager
    `- /xyz/openbmc_project/inventory
      `- /xyz/openbmc_project/inventory/system
        `- /xyz/openbmc_project/inventory/system/board
          |- /xyz/openbmc_project/inventory/system/board/NVIDIA_Alon_cx8_Fru
          | `- /xyz/openbmc_project/inventory/system/board/NVIDIA_Alon_cx8_Fru/NVIDIA_Alon_cx8_Fru
          |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_50
          | |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_50/GPU_0
          | |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_50/GPU_0SMA
          | `- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_50/NVIDIA_RTXPro6000_50
          |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_51
          | |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_51/GPU_1
          | |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_51/GPU_1SMA
          | `- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_51/NVIDIA_RTXPro6000_51
          |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_54
          | |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_54/GPU_2
          | |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_54/GPU_2SMA
          | `- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_54/NVIDIA_RTXPro6000_54
          |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_55
          | |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_55/GPU_3
          | |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_55/GPU_3SMA
          | `- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_55/NVIDIA_RTXPro6000_55
          |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_58
          | |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_58/GPU_4
          | |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_58/GPU_4SMA
          | `- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_58/NVIDIA_RTXPro6000_58
          |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_59
          | |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_59/GPU_5
          | |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_59/GPU_5SMA
          | `- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_59/NVIDIA_RTXPro6000_59
          |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_62
          | |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_62/GPU_6
          | |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_62/GPU_6SMA
          | `- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_62/NVIDIA_RTXPro6000_62
          `- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_63
            |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_63/GPU_7
            |- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_63/GPU_7SMA
            `- /xyz/openbmc_project/inventory/system/board/Nvidia_RTX6000_GPU_63/NVIDIA_RTXPro6000_63
```

Change-Id: Ie524d8444be2cc19061227455ba71b4f61ee6683
Signed-off-by: Marc Olberding <molberding@nvidia.com>
2 files changed