[llvm] [Offload] Remove unnecessary omp CMake target dependencies (PR #149060)

[Joseph Huber via llvm-commits]

jhuber6 wrote:

> IIRC there are indeed some function calls from `libomptarget` to `libomp`.

Yeah, there are a few but I forget which ones. Did this really build and pass the tests?

https://github.com/llvm/llvm-project/pull/149060