[PowerPC] force applications linked with lib CSU to have .got

Summary:
This forces applications linked with lib CSU to have a .got, fixing binaries
linked with LLD9 after secure-plt was enabled on FreeBSD.

Submitted by: Alfredo Dal'Ava Junior (alfredo.junior_eldorado.org.br)
Differential Revision: https://reviews.freebsd.org/D21476