Investigate hip types BF16 and FP8

[CharlieL7]

New headers hipamd/include/hip/amd_detail/amd_hip_bf16.h and hipamd/include/hip/amd_detail/amd_hip_fp8.h should be in the latest ROCm release? Will we be incorporating these?

[pfultz2]

I dont see a reason to use the bf16 header since we already use the compiler type directly(which enables us to use vector types).

The fp8 header will be useful to remove our special fp8 type on the GPU.