GMPLS update - 58: optimizing standard in-segment entries

Optimized #standard #in-segment #entries in GMPLS module. This #removes the #attributes like #pointer to #extra #parameters. The hard-linked #custom #in-segment entries provides the extra #parameters on the segment which satisfies the same requirement. The custom in-segment entry holds attributes like in-label. This will reduce the memory requirement associated with the in-segment entries.

#GMPLS update 58 ...
[commit f33ba928d0f83db848881c9fd6264d77415288ee] (https://github.com/nes-repo/NES-Open-Switch/commit/f33ba928d0f83db848881c9fd6264d77415288ee)