c75895c726
hipamd backend has new unsafeAtomicAdd() and safeAtomicAdd() functions,
and modifications to how it interactsion with -m[no-]unsafe-fp-atomics
compiler options. Update documentation to reflect this.
Change-Id: I2659c2ee1bfe21d870dd1d17cae993dfa170c3f5
[ROCm/hip commit: e58351465f]