Add mlxlink status collection to techsupport

[tshalvi]

What I did

Added support for collecting mlxlink status as part of the techsupport dump.

How I did it

• Implemented a new function to normalize and interpret port alias/index values and convert them into the mlxlink panel numbering format.
• Added a new mlxlink collection routine that iterates over all logical ports, resolves their panel identifiers, invokes mlxlink, and records the results.

How to verify it

Run 'show techsupport' and confirm the generated dump includes
dump/mlxlink.status containing the mlxlink status for all ports.

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

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