Add missing dep on MLIRToLLVMIRTranslationRegistration to mlir-opt. (#75111)

I was not able to fully triage why this just started failing on one of
our bots as it seems that the use was added 4 months ago. I would assume
that it was accidentally coming in transitively in some way as the dep
was definitely missing.

For context, this started failing in [our
byo_llvm](https://github.com/openxla/iree/blob/main/build_tools/llvm/byo_llvm.sh)
build on a stock build of MLIR on top of an existing LLVM. We were
getting:

```
ld.lld: error: undefined symbol: mlir::registerSPIRVDialectTranslation(mlir::DialectRegistry&)                                                        >>> referenced by mlir-opt.cpp
>>>               tools/mlir-opt/CMakeFiles/mlir-opt.dir/mlir-opt.cpp.o:(main)
```