include/opt: Remove unnecessary array __opt_long

include/opt: Remove unnecessary array __opt_long

The data that is stored in opt's __opt_long array is a subset of
the data stored in __opt_map. The operations that the module does
on __opt_long might just as well be performed on __opt_map without
affecting the behavior of the module.

This commit removes the __opt_long array from the module and
changes the affected functions to use __opt_map instead.