[TASK] Understand the LLVM/AMD codenames for GPU architectures

[dipietrantonio]

Many libraries allow optimizations based on GPU architecture. You can specify what architecture you want to compile the library for, by using the CMake flag AMDGPU_TARGETS=... For the MI100, the code gfx908 seems valid (i.e. no errors thrown), but on AMD Readmes, gfx908:xnack- is found often. We need to understand exactly what to ask for. The answer lies here: https://llvm.org/docs/AMDGPUUsage.html