After the change in commit I75f0b76ae920c885a1150d95ea011e5612ef62fd,
the gNeighborLookupThreshold INI value will be a negative number. This
update ensures that the INI comment accurately reflects the change.
Additionally, existing INI files may still include a positive number
(e.g., 76). To maintain compatibility, the default value is updated to
-76 in case the INI files haven't been updated to use negative numbers.
Change-Id: I1c588fcbc5716d9efadf1272842d60a29c26eba6
CRs-Fixed: 3826341
897a0fac50