[Smartswitch][nvidia-bluefield]Add watchdog device mount for pmon #55

[gpunathilell]

Why I did it

The watchdog arm/disarm will fail in the pmon container with the following error:

root@sonic:/# mlxbf-bootctl
/dev/mmcblk0: No such file or directory
root@sonic:/#

Because the container hardening feature required explicit device mounting. This is fixed by mounting the dpu watchdog device for the pmon container, since we have platform apis in the containers which are called during sonci-mgmt tests

Work item tracking

• Microsoft ADO (number only):

How I did it

Mount the DPU watchdog relevant device.

How to verify it

Arm/check the watchdog status in the pmon container, with the watchdog platform api object.

Which release branch to backport (provide reason below if selected)

• 202205
• 202211
• 202305
• 202311
• 202405
• 202411
• 202505

Tested branch (Please provide the tested image version)

Description for the changelog

Link to config_db schema for YANG module changes

A picture of a cute animal (not mandatory but encouraged)

[mssonicbld]

/azp run Azure.sonic-buildimage

[azure-pipelines]

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