Replace amd::Atomic with std::atomic. Remove make_atomic uses by
converting the variable to std::atomic and making sure the memory
order is relaxed when synchronizes-with is not needed.
Delete utils/atomic.hpp.
Change-Id: I0b36db8d604a8510ac6e36b32885fd16a1b8ccfa
[ROCm/clr commit: 5d4b6f74d3]
Jason Tang
Laurent Morichetti