[MLIR] Missing declaration build fix

The sanizer bots are reporting a missing declaration:

```
In file included from /home/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/mlir/lib/Dialect/LLVMIR/Transforms/InlinerInterfaceImpl.cpp:17:
In file included from /home/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/mlir/include/mlir/Dialect/LLVMIR/NVVMDialect.h:26:
/home/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/mlir/include/mlir/Target/LLVMIR/ModuleTranslation.h:318:34: error: no type named 'CallBase' in namespace 'llvm'
  318 |                            llvm::CallBase *call,
      |                            ~~~~~~^
1 error generated.
```

https://lab.llvm.org/buildbot/#/builders/94/builds/9340
https://lab.llvm.org/buildbot/#/builders/24/builds/11029
https://lab.llvm.org/buildbot/#/builders/169/builds/13454
https://lab.llvm.org/buildbot/#/builders/25/builds/10250

PR llvm#151302 removed some indirect header #includes which had to be
includes explicitly. I do not know why this particular error only occurs
with the sanitizer buildbots.

Fix by adding a forward declaration.

Author: Meinersbur

mlir/include/mlir/Target/LLVMIR/ModuleTranslation.h

@@ -30,6 +30,7 @@
 
 namespace llvm {
 class BasicBlock;
+class CallBase;
 class CanonicalLoopInfo;
 class Function;
 class IRBuilderBase;