[OpenMP] libomptarget: eliminate compiler warnings at build

Thanks to Sergey Dmitriev for submitting the patch.

Differential Revision: https://reviews.llvm.org/D33851



git-svn-id: https://llvm.org/svn/llvm-project/openmp/trunk@304601 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed