lib: utils: Generalize parse_one_of()

lib: utils: Generalize parse_one_of()

The following patch will change the way parse_one_of() and parse_on_off()
parse the strings they are given. To prepare for this change, extract from
parse_one_of() the functional core, which express in terms of a
configurable matcher, a pointer to a function that does the string
comparison. Then rewrite parse_one_of() and parse_on_off() as wrappers that
just pass matches() as the matcher, thereby maintaining the same behavior
as they currently have.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: David Ahern <dsahern@kernel.org>