[llvm] [AMDGPU] Allow lit() on operands which do not accept modifiers (PR #69527)

[Jay Foad via llvm-commits]

https://github.com/jayfoad approved this pull request.

> > > This looks OK but I'm not too familiar with operand parsing. Is there a cleaner way to implement this, so that we don't have two different places where "lit" is parsed?
> > 
> > It boils down to the place where we have to create an operand. That is where I have to set modifiers. I can guess there might be a better way, but this would literally mean rewriting everything, not just parser. I found this a lesser evil.

LGTM then. We can always rewrite it later...

https://github.com/llvm/llvm-project/pull/69527