[mlir][NFC] Remove stale createLowerAffinePass declaration

This pass isn't defined in the Transforms/ library anymore.

mlir/include/mlir/Transforms/Passes.h

@@ -82,11 +82,6 @@ std::unique_ptr<Pass> createLoopInvariantCodeMotionPass();
 /// memory hierarchy.
 std::unique_ptr<OperationPass<FuncOp>> createPipelineDataTransferPass();
 
-/// Lowers affine control flow operations (ForStmt, IfStmt and AffineApplyOp)
-/// to equivalent lower-level constructs (flow of basic blocks and arithmetic
-/// primitives).
-std::unique_ptr<Pass> createLowerAffinePass();
-
 /// Creates a pass that transforms perfectly nested loops with independent
 /// bounds into a single loop.
 std::unique_ptr<OperationPass<FuncOp>> createLoopCoalescingPass();