LAG upgrade - 23: updating custom member port parameters agent mapper routines

Updated #custom #member #port parameters agent routines in LAG module. The agent #iterator routines and #mapper #routine has been updated to use standard #member #port #based #indexing. This will access the member list embedded in the member port and there by removing the redundant indexing. The custom member port entries holds the attributes like the #port-aggregator-group, #LACP-enable, #LACP-passive-enable, #LACP-slow-timer-enable, #dynamic-key-management-enable, etc ...

#LAG update 31 ...
[commit 6b0684762704ec6761239fa553fd50fda10d7fe0] (https://github.com/nes-repo/NES-Open-Switch/commit/6b0684762704ec6761239fa553fd50fda10d7fe0)