Implement target builtins for gfx90a including fadd64, fadd32, add2h, max and min on various global, flat and ds address spaces for which intrinsics are already implemented.
@rampitec Compiler recommended me to add global-noret target feature after setting it in BuiltinsAMDGPU.def. I am not sure what that means outside of the BuiltinsAMDGPU.def so I have changed it back to gfx90a-insts.
Correct attribute for this one in atomic-fadd-insts. In particular it was first added in gfx908 and you would need to test it too.