[SYCL][Fusion] Fix build error: call to deleted constructor (#8619)

When building with `clang version 11.0.0`:
```
sycl-fusion/passes/kernel-fusion/Builtins.cpp:583:16: error: call to deleted constructor of 'llvm::Error'
        return Err;
               ^~~
```

Signed-off-by: Tsang, Whitney <[email protected]>

Author: whitneywhtsang

sycl-fusion/passes/kernel-fusion/Builtins.cpp

@@ -583,7 +583,7 @@ jit_compiler::Remapper::remapBuiltins(Function *F, const NDRange &SrcNDRange,
       auto *OldF = Call->getCalledFunction();
       auto ErrOrNewF = remapBuiltins(OldF, SrcNDRange, FusedNDRange);
       if (auto Err = ErrOrNewF.takeError()) {
-        return Err;
+        return std::move(Err);
       }
       // Override called function.
       auto *NewF = *ErrOrNewF;