userspace/snmpd: (no tech change) rename fields in the wrsPstatsHCTable_s

Rename fields in the struct wrsPstatsHCTable_s to reflect SNMP objects'
names (add "wrsPstatsHC" prefix).

As a side effect do the same with struct ns_pstats.

--Changes in wrsPstatsHCTable_s:
index -> wrsPstatsHCIndex
port_name[12] -> WrsPstatsHCPortName[12]
TXUnderrun -> wrsPstatsHCTXUnderrun
RXOverrun -> wrsPstatsHCRXOverrun
RXInvalidCode -> wrsPstatsHCRXInvalidCode
RXSyncLost -> wrsPstatsHCRXSyncLost
RXPauseFrames -> wrsPstatsHCRXPauseFrames
RXPfilterDropped -> wrsPstatsHCRXPfilterDropped
RXPCSErrors -> wrsPstatsHCRXPCSErrors
RXGiantFrames -> wrsPstatsHCRXGiantFrames
RXRuntFrames -> wrsPstatsHCRXRuntFrames
RXCRCErrors -> wrsPstatsHCRXCRCErrors
RXPclass0 -> wrsPstatsHCRXPclass0
RXPclass1 -> wrsPstatsHCRXPclass1
RXPclass2 -> wrsPstatsHCRXPclass2
RXPclass3 -> wrsPstatsHCRXPclass3
RXPclass4 -> wrsPstatsHCRXPclass4
RXPclass5 -> wrsPstatsHCRXPclass5
RXPclass6 -> wrsPstatsHCRXPclass6
RXPclass7 -> wrsPstatsHCRXPclass7
TXFrames -> wrsPstatsHCTXFrames
RXFrames -> wrsPstatsHCRXFrames
RXDropRTUFull -> wrsPstatsHCRXDropRTUFull
RXPrio0 -> wrsPstatsHCRXPrio0
RXPrio1 -> wrsPstatsHCRXPrio1
RXPrio2 -> wrsPstatsHCRXPrio2
RXPrio3 -> wrsPstatsHCRXPrio3
RXPrio4 -> wrsPstatsHCRXPrio4
RXPrio5 -> wrsPstatsHCRXPrio5
RXPrio6 -> wrsPstatsHCRXPrio6
RXPrio7 -> wrsPstatsHCRXPrio7
RTUValid -> wrsPstatsHCRTUValid
RTUResponses -> wrsPstatsHCRTUResponses
RTUDropped -> wrsPstatsHCRTUDropped
FastMatchPriority -> wrsPstatsHCFastMatchPriority
FastMatchFastForward -> wrsPstatsHCFastMatchFastForward
FastMatchNonForward -> wrsPstatsHCFastMatchNonForward
FastMatchRespValid -> wrsPstatsHCFastMatchRespValid
FullMatchRespValid -> wrsPstatsHCFullMatchRespValid
Forwarded -> wrsPstatsHCForwarded
TRURespValid -> wrsPstatsHCTRURespValid

--changes in ns_pstats:
TXUnderrun -> wrsPstatsHCTXUnderrun
RXOverrun -> wrsPstatsHCRXOverrun
RXInvalidCode -> wrsPstatsHCRXInvalidCode
RXSyncLost -> wrsPstatsHCRXSyncLost
RXPfilterDropped -> wrsPstatsHCRXPfilterDropped
RXPCSErrors -> wrsPstatsHCRXPCSErrors
RXCRCErrors -> wrsPstatsHCRXCRCErrors
RXFrames -> wrsPstatsHCRXFrames
RXPrio0 -> wrsPstatsHCRXPrio0
RXPrio1 -> wrsPstatsHCRXPrio1
RXPrio2 -> wrsPstatsHCRXPrio2
RXPrio3 -> wrsPstatsHCRXPrio3
RXPrio4 -> wrsPstatsHCRXPrio4
RXPrio5 -> wrsPstatsHCRXPrio5
RXPrio6 -> wrsPstatsHCRXPrio6
RXPrio7 -> wrsPstatsHCRXPrio7
FastMatchPriority -> wrsPstatsHCFastMatchPriority
RXDropRTUFull -> wrsPstatsHCRXDropRTUFull

Signed-off-by: Adam Wujek <adam.wujek@cern.ch>