[llvm] Revert "[NVPTX] Lower 16xi8 and 8xi8 stores efficiently (#73646)" (PR #74518)

[Artem Belevich via llvm-commits]

Artem-B wrote:

I'll hold off on revert until tomorrow, so @bondhugula may have a chance to fix it forward.

https://github.com/llvm/llvm-project/pull/74518