[NFC][Bitcode] Remove unused param in DataLayoutCallbackTy

[aeubanks]

No description provided.

[nikic]

The argument was added in https://reviews.llvm.org/D140985.

[jasilvanus]

Thanks @nikic.

We rely downstream on the second argument when importing DXIL in order to fix invalid i8 alignment without using a hardcoded DL string. Instead, we just set natural alignment for i8 in the existing DL string.

I think it's quite natural to feed the DL string of a module into the callback to allow inspection of the existing string?
Maybe we should document the intended usage and downstream dependency better though, not sure on the policy for such things.

[aeubanks]

happened to see this when attempting to refactor some code, abandoning