[CI] Added MLD tool

• Related issues: None
• Requested reviewers: @kiene, @pihlajakuja

Reason why this change is needed

• Add MLD tool to be used in BASOP CI.

Description of the change

• Adds CI tool to cmp_pcm.py which in turn uses audioarray.compare. Should be transparent to the current PC CI, since the MLD option is not enabled there.

Affected operating points

CI only