MSTP update - 12: hard-linking CIST configuration entries

#Hard-link ed #CIST #configuration entries through #standard #STP #instance #entries in MSTP module. This will indicate the extended CIST attributes like #regional-root identifier, the #path-cost to the regional-root, #max_hop parameter, etc ... This will reduce the memory requirement associated with the CIST entries. The hard-linked CIST entries enables accessing them directly from the standard STP instance entries.

#802-1S #MSTP update 12 ...
[commit f27a76eae301bb6adb6ace64c6e5b92f9cb25e1c]