[llvm] [NFC] Fix deprecated use of lookupTarget in Kaleidoscope (PR #162220)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 approved this pull request.

LGTM. Thanks for the fix.

Interesting that this doesn't seem to be wired up to build under `LLVM_BUILD_EXAMPLES`.

https://github.com/llvm/llvm-project/pull/162220