Revert "[libomptarget] Build amdgcn devicertl by default"

This reverts commit e23f3502d9a2b1e9abd445130a22cc00f6464da8.
It broke the build of openmp for clang built without amdgcn
support. D98746, under review, would allow this to reland.

GitOrigin-RevId: dbf8f2b089e842d445442a25a0aee78e3b3b500d
2 files changed