Added CMake changes for building HIP/ROCm CUDA for AMD GPUs.

[aldorof]

The same way it's realised on llama.cpp. So that one can build CUDA BLAS for HIP with something like this:

CXX=hipcc CC=hipcc cmake -DWHISPER_HIPBLAS=ON -DAMDGPU_TARGETS="gfx1100;gfx1101;gfx1102" -DBUILD_SHARED_LIBS=ON ../whisper.cpp