[PPC64] Preserve LocalEntry when linking

On PowerPC64, it is necessary to keep the LocalEntry bits in st_other,
especially when -r is used. Otherwise, when the resulting object is used
in a posterior linking, LocalEntry info will be unavailable and
functions may be called through the wrong entrypoint.

Patch by Leandro Lupori.

Differential Revision: https://reviews.llvm.org/D56782

llvm-svn: 354184