Revert b370e46b370e46... Put longest options first

This reverts commit b370e46abdd2bfe764e28efb41c4caadc632b937.

We should not have to do this, and the commit was even buggy since
it mistakenly put mmap inside the mmaphuge ifdef section. Just make
parse sort the posval entries.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>