These are redundant with the unsuffixed versions, and have a name
collision with surprising behavior when the base intrinsic is used with
v2bf16.
The global and flat variants should be removed too, but those are complicated
due to using v2i16 in place of the natural v2bf16. Those cases can soon be
completely deleted in favor of atomicrmw.
The GlobalISel codegen change is broken and substitutes handling as bf16
for handling as f16, but it's a bug that this passed the IRTranslator in the first
place.
