Bridge port update - 16: correcting MRP referencing

#Referencing #bridge #MRP #configuration entries #through standard #bridge #port configuration in ethernet module. Corrected MRP agent iterator routines and mapper routines to use the standard bridge port references than using a dedicated indexing.

#Ethernet update 116 ...
[commit 3497e2f46136ad732286733ce9d989ba96411d46]