[clang] [clang] remove non-functional SrcAddr parameter from performAddrSpaceCast (PR #179330)

[Eli Friedman via cfe-commits]

efriedma-quic wrote:

@arsenm @yxsamliu Are we missing anything here?

(I don't care that much whether we do the additional cleanup in this patch, if we're sure this is what we want.)

https://github.com/llvm/llvm-project/pull/179330