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

[Stanislav Mekhanoshin via llvm-commits]

rampitec wrote:

> 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.

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