Revert "make: allow building flat binary plugins on USE_ELF targets"
This reverts commit 91ec6f1e1efe41577c2414cfcf62ec86d4a90e95.
Reason for revert: Massive sea of red, looks like hosted + sim builds.
Change-Id: I98a3954d68ad2cc521e13c3683bf4a6f45f88b36