feat: toy tutorial chapter 6.

Signed-off-by: jackfiled <xcrenchangjun@outlook.com>

include/Passes.h

@@ -16,6 +16,8 @@ namespace mlir
         std::unique_ptr<Pass> createShapeInferencePass();
 
         std::unique_ptr<Pass> createLowerToAffineLoopsPass();
+
+        std::unique_ptr<Pass> createLowerToLLVMPass();
     }
 }