[clang] [OpenCL] Replace a CreatePointerCast call; NFC (PR #112676)

[Youngsuk Kim via cfe-commits]

JOE1994 wrote:

Oh.. `CreateAddrSpaceCast` calls `CreateCast` which also initially checks whether `to` and `from` types are identical before emitting anything.

https://github.com/llvm/llvm-project/pull/112676