Hi,
I believe there is no such standard report but you can try with table KNVP in SE16N.
Go to the table Se16N.....Unselect all the selection parameters and select ONLY Customer and Partner Function and execute. later you can filter on the Partner function column.
You can also try VC/2 but the problem is that its a fact sheet and it is slow . It is OK for a single customer if you wanted to see what all PF the customer has.
Regards
PJ