[Libomptarget] Remove undefined symbol in old runtime

A function with no definition was left in the old runtime, causing
linker errors when trying to compile.

Reviewed By: tianshilei1992

Differential Revision: https://reviews.llvm.org/D114264

GitOrigin-RevId: fbfe8fcbc31d492d5538c09782b787bba89d01e5
1 file changed