[llvm] [SPIRV] Do not remove capability from all caps (PR #68194)

[Paulo Matos via llvm-commits]

pmatos wrote:

> > I initially added this code but I think I misinterpreted the purpuse of AvailableCaps.
> 
> Well, we needed to use `AllCaps` instead of `AvailableCaps`.

You are correct yes, I should have used AllCaps instead of AvailableCaps.

https://github.com/llvm/llvm-project/pull/68194