hptnr: Store the .o files directly in the repo

We no longer need to use uuencode to uuencode files in our tree. Store the .o
file directly instead. Adjust the build to cope with the new arrangement.

Suggestions by: emaste, bz, donner
Reviewed by: markm
Sposnored by: Netflix, Inc
Differential Revision: https://reviews.freebsd.org/D29632