[flang] Build broken due to no member named 'getNumScalableDims' in...

[flang] Build broken due to no member named 'getNumScalableDims' in 'mlir::VectorType' after D153412 (NFC)

/data/llvm-project/flang/lib/Optimizer/Dialect/FIROps.cpp:971:46: error: no member named 'getNumScalableDims' in 'mlir::VectorType'
    if (mlir::dyn_cast<mlir::VectorType>(ty).getNumScalableDims() == 0)
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^
1 error generated.