[MLIR] Add missing MLIRFuncDialect dep to MLIRMemRefToLLVM (#84546)

This fixes the following failure when doing a clean build (in particular
no .ninja* lying around) of lib/libMLIRMemRefToLLVM.a only:
```
In file included from mlir/lib/Conversion/MemRefToLLVM/MemRefToLLVM.cpp:18:
mlir/include/mlir/Dialect/Func/IR/FuncOps.h:29:10: fatal error: mlir/Dialect/Func/IR/FuncOps.h.inc: No such file or directory
```