Add check_pfc_storm_active() to fast-reboot script

[hdwhdw]

What I did

Added the check_pfc_storm_active() function to the fast-reboot script to ensure consistent PFC storm detection across all fast-reboot implementations.

How I did it

• Added EXIT_PFC_STORM_DETECTED=25 exit code constant
• Implemented check_pfc_storm_active() function that uses pfcwd show stats to detect active PFC storms
• Updated reboot_pre_check() to call the new function before proceeding with reboot
• The function aborts warm-reboot if PFC storm is detected to prevent failure in recovery path

How to verify it

1. Run fast-reboot on a system without PFC storm - should proceed normally
2. Simulate PFC storm condition and run fast-reboot - should abort with appropriate error message
3. Verify the function is called during reboot pre-checks

Previous command output (if the output of a command-line utility has changed)

N/A - No change to command output, this is an internal safety check

New command output (if the output of a command-line utility has changed)

N/A - No change to command output, this is an internal safety check

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[vaibhavhd]

Can you check if this value can be obtained from DB? Depending on grep is dangerous, particularly when it is not strict.